FIL recently got a little 18' TT to use during the summer months - his big 5'ver stays in storage down @ Lake Havasu. The one he found was a bunk bed model... and he's discovered that after years and years in first a big class A motorhome, and later the big 5th wheel, he's gotten spoiled by not having to watch his head ;)
We've been discussing possible mods along similar lines - removing the top bunk entirely, making the top bunk height adjustable, etc. I'd be interested to hear what others might have come up with.