dave
there is not gonna be a way around the 2 gig limit. what we all do is edit each file, track out in cd wave then paste the two tracks together where the file split (in wavelab). or if for now you just want the 16 bit tracked etc....
do all editing in 24 bit. then resample, dither (in that order) all the files. then you should be able to paste them all together as one 16 bit file to track.
edit: it's not a vista thing or wavelab per say. it's a windows thing in general.