Ok, much as I would like him to be in it, it looks unlikely at this point. Filming is virtually over and Liam has categorically said he wasn't it- not spilling the beans is one thing, but he wouldn;t have directly LIED about it, I don't think.
It would cause a lot of arguments about the Ghost Trick as well...
Uh, qui-gon IS in attack of the clones. in the scene where obi-wan goes to see jocasta in the jedi library, it is revealed that dooku was qui-gons master and there is holo footage of qui-gon and dooku fighting side by side. liam neeson shot footage with christopher lee a few months ago in london, if i remember correctly. anyways, this whole subject was discussed to no end in a thread thats not too far down on the list. its called "a jedi never dies" or something like that. no reason to discuss it all over again.