So just the basic ideas, would be happy to flesh them out if wanted.
Most would require a new line of magic, atleast im presuming new, but may have
had it before.. That being 'dream' magic.

Sleep Sage (Good-relig)
Main focus, on being able to cast whilst sleeping, and able to induce positive
sleeping buffs on party. For example Deep sleep spell, would put an already
sleeping party member into a better level of sleep, increasing regen
drastically, but would require waking up via another skill/spell from sage.
Skills such as sleep talk, allowing the sage to cast whilst sleeping, sleep
walk, to move whilst sleeping etc...

Dream Eater (Evil-relig)
Main focus, putting things into deep sleep and eating theyre hp via dream
magicky goodness. Would have skills that have better chance of not waking
sleeping enemies whilst casting at them such as dream snatch,catch aswell as
utility spells to put mobs to sleep, even during combat. The better the levels
in skills and masteries of these would determine how much hp the mob could
loose before waking up again.

Walker (nomad) Purely a utility focused guild to allow the user to still
function whilst under buffs from sage and the like. Increased regen for
sleeping and skills like dream blade, allowing nomad to fight poorly (to ok at
later levels) even whilst sleeping.

Dream weaver (magical) Same line as the other blasty mage guilds, only with all
spells doing more damage to sleeping enemies. Could also go down the illusion
type magic route.

Dream blade (civ) Focuses on keeping combat passives at good levels even whilst
sleeping, for example waking parry, slothful dodge, sleep tight eyesight etc..

Anyhow, lots of other stuff, but that should be enough to get the idea of them
xD