Been there, done that . See Endless Planes.
Realms of Morpheus and Hypnos
Hypnos Lesser Power, God of SleepAlignment: N (NG tendencies)Realm: Mansion of Rest, Deep EtherealSmall by deity standards, Hypnos's realm is a floating island near the border between the Deep Ethereal proper and the Dreamscapes. The power lives in a finely decorated manse filled with various magical items capable of inducing sleep or awakening one from slumber. Additionally, Hypnos has collected riches from across the multiverse, given in return for an assortment of favors the god has performed over the millennia. The various players of the Cosmic Game seek the aid of the Sleep Bringer, for his magic can induce a moment of slumber in even some Greater Powers! This has also led Hypnos to be distrusted, for while the power is amicable enough, even to mortal visitors, one wonders about his true agenda. The proximity of the mysterious dream realms has only made the other immortals wary.When entertaining visitors Hypnos appears as a winged youth clad in flowing white clothes. He resembles nothing more than an astral deva of regal bearing yet humble soul. Mortals will find nourishment and rest so long as they do not seek to harm the power or his servants. Those foolish enough to do so slumber in his cellar for eternity. In addition to serving as a rest stop and source of sleeping agents magical and mundane, Sleeper's Gate possesses a portal to the realm of Morpheus that circumvents the dangers inherent to traveling through the dreams of others. While the relationship of their portfolios is clear, their family relationship is not. Most agree Hypnos is Morpheus's father, while others say they are in fact brothers.
MorpheusIntermediate Power, God of DreamsAlignment: NRealm: City of Dreams, Dream HeartProxies: Phobetor and Phantasos, quasi-deities"Dear guest, Dreams (Oneiroi) are beyond our unravelling - who can be sure what tale they tell? Not all that men look for comes to pass. Two gates there are that give passage to fleeting Oneiroi; one is made of horn, one of ivory. The Oneiroi that pass through sawn ivory are deceitful, bearing a message that will not be fulfilled; those that come out through polished horn have truth behind them, to be revealed to men who see them. But I cannot hope that this Oneiros (Dream) that bewilders me came from there." - Odyssey 19.562The realm of Morpheus is said to lie in the mysterious region of dreams known as the Dreamheart. Mutable as dreams are, visitors have described the realm as a massive graveyard filled with undead children as well as an orchard where columns of light represent the sum total of the multiverse's love. However, the home of the god himself remains fairly constant. A cavern from which issues a soft glow of shifting colors, surrounded by a wall made of swirling ether. Those who attempt to pass through are sent into random dreamscapes or on the other side of the Wall of Color, though they might spend months wandering through the ethereal wall before facing this disappointment. Fortunately there are two gates placed side by side that lead into the cavern, though they are not always present. One is seemingly formed from two bull horns twisting together, the other carved from ivory ironically depicting images of prophetic dreams that have shaped the multiverse in times past.The walls, ceiling, and floor of this cave are formed from crystal. Within the crystals are reflections of the myriad dreamscapes, which are seen as glowing white motes within what seems to be amethyst. As one goes deeper into the cavern, one will meet various shamans, astral travelers, wizards, and even disguised gods coming to trade in dreamstuff. In the cavern's heart lies the City of Dreams. A great city was formed from the crystal where the ceiling is highest, a massive cave dwelling where beings from the other side of dreams can visit our multiverse. Several species of visitor do not seem fully there, and some have clearly defined silver cords trailing behind them. Trusting in Morpheus, they walk without fear of githyanki passerby, who in turn seem to have cast off the chains of the lich queen. The peace is kept by the nightmarish bats that hang from the stalactites. It is said these are Morpheus's lesser siblings, the Oneiroi--dreambringers. Supposedly those who bring prophetic or insightful dreams pass through the gates of horn, and the rest through gates of ivory. Yet it has been noted that a bat will fly through one gate, then circle through the other before flying out of the cavern.Within the realm those enveloped by the Oneiroi's shadowy wings are forever plagued by nightmares both in waking and in sleep. If this were not threat enough, the brothers Phobetor and Phantasos run the city at their elder brother's behest. Phobetor appears as a male carved from black marble, save that white flecks and streaks blaze on his skin like lightning. Phantasos appears to be made from onyx, a red glow shining faintly where his heart should be. These two are the hands of Morpheus, charged with governing and defending the Dreamheart from enemies such as the dreamlarvae. Phobetor is able to pull out weapons or allies from any dream, and Phantasos can either banish enemies into any dream or wake up dreaming beings. Of the two, Phobetor is the more easily approached, willing to share information and advice with dream travelers. Phantasos rarely speaks, and only then to give warning or pass sentence before he awakens a dreamer and thus shatters a dreamscape. The Dream Wanderers, a group similar to the Planewalker's Guild, apparently cross multiverses through dreams and are made most welcome here. In fact, some of these mortals are said to be in council with Morpheus himself regarding a strange tower that seems to exist within and yet independently of dreaming minds.
I like the idea of giving a realm to Morpheus, and overall, I find the stuff correct. I miss only one or two elements: the Gate of Ivory and the Gate of Horn (for true and false dreams), for example. A good source on dream-related realms and creatures is Neil Gaiman's Sandman, so it might be worth checking.