Per core, once you leave Monk you can never go back, as far as I know. FR introduced some specific things that let you multiclass between monk and a specific class by taking a feat or something and being part of a special group.
I've seen one or two non-pure monk builds ... mostly some people take Mnk 1 for the across-the-board Save boost and some unarmed damage for the off-days when the DM thinks he's being original and has everybody wake up in their skivvies under attack. I've played one monk, in a Psionics based campaign, as a Psionic Hole type. Anti-psionics feats up and down the board and insane grapple ability. Was a nice build until I realized that even with some specialized feats like Clever Wrestling, I could barely hold my own against Large creatures and was useless against anything bigger than that, while a regular ole' Fighter would have been useful every day including Sunday. Death on wheels against humanoid casters, though. Flash across the room, grapple ... that's all she wrote.
Then a dragon kicked our rears ... dragons really presuppose magic, I think, and the DM went Psionics-Only.
I'd leave Jedi out of a D&D game. There's alot of ways to make a D&D game your own, but the styles these two games were created for, while high powered, are pretty different.
--fje