Please excuse my pessimism. Both JME and Xith3d are excellent engines, I'm just pointing out the problems I've found with them. Are there any other engines I should take a look at?
TBH I doubt you'll find many other options. What do you need, that the existing engines can't deliver? I would think JME is mature enough for any non-bleeding-edge game and xith is small enough to fix bugs as you'll find them. Also if you really need "commercial" support, I am a freelance programmer, so hire me

If you really book comercial support we would branch a version just for you...