I think the concern (obsession, if you will) is not waiting for a Mactel PowerBook but for a "Revision D" G4 --- the last update to the current Al PowerBook lines.
Will Paris Expo produce this type of update? If not, I don't foresee any in the near future, at least not this year. Remember last year? An April '04 update, then rumors up the creek about an October refresh to 1.8Ghz. Nothing happened. Nothing, in fact, until a lame, quiet, unassuming update on Jan. 31 of '05.
Apple, in fact, knows that perpetuating a rumor mill is big business, not only for themselves, but for psychiatrists everywhere --- Mac fiends suffer, no doubt, from OCD complexes. Just take a glance at these forums.