I think I know how you feel since I went thru somewhat similar circumstances. I have 3 dogs, Lucy, Chedder, and Gus. Gus is the youngest and gets along with everyone. But Lucy and Chedder are the same age and sometimes will fight over who gets to play with what toy, who gets to eat or drink first, and in some cases, who gets to sleep in which bed (I have three seperate beds, plus an old cat bed our neighbors gave to us that Gus can actually fit into).
Lucy and Chedder will only fight over beds, it seems, when either one tries to switch beds late at night and its dark so that either one of them panics when they feel the other trying to invade their snuggly bed. And sometimes Lucy will just occasionally wander over to Chedder while he's asleep and either sit and stare at her or sniff/lick her face. I don't know why he does this but if I were asleep and someone started doing that to my face, I'd wake up in a foul mood too ^^
I did try what you tried, putting Lucy in a closet bed, I had the closet door closed all the way so she couldn't get up and bother Chedder. But then she'd wake up at all hours of the night, pawing at the door or whining or even barking. So that didn't work out. (I theorize that maybe she got nervous/anxious at not being able to see me or the other dogs and woke up randomly). This might happen, too, if you close off your other dog in another room. It might start whining or barking to come join you.
So my solution, one that finally worked, was getting one of those little baby-gates. Found mine at Babies'R'Us and it comes in either square or Hexagon-shaped. Mine was on sale for $29. I put the baby gate around Chedder's bed and then Lucy gets her own bed, un-gated.
That way, Lucy can still see where we are, yet gets her own private space.
It's worked out since I got the baby gate in 2001 so I'd said give that a try.
Hope everything works out between you and your furry friends!