No, you can't pair them up with another animal. They can and will attack them if they're together. Plus, none of the animals you mentioned climb or glide like a glider, and most of the gliders I've had spend virtually all day up in the air.
Really, your best option is to get him a friend and a bigger cage. I understand that can be expensive, but that's part of owning a pet. It's concerning because if he has any medical issues, they will likely cost way more than another glider and a cage.
If you're still in VA, there's no statewide prohibition on gliders -- there are several active breeders there. [I'm in NC and get rescue gliders in from up there all the time]
We are as gods to the beasts of the fields. We order the time o' their birth and the time o' their death. Between times, we ha' a duty. - Terry Pratchett.
"Men have forgotten this truth", said the fox, "But you must not forget it. You become responsible, forever, for what you have tamed. - Antoine de Saint-Exupéry