I've heard of people squeezing 1200 engines into Bandit 600s, but I don't think it would be quite so easy with the Fazers
Normally I'm all for mods, but...... 40+ more ponies into a 600 which was fairly budget in terms of frame & suspension setup? Surely the engine bay within the 600's frame would be too small & there'd be no room for any sort of airbox (or even filters)? Engine mounting points around the frame would also differ both in position and diameter on the 600. You might need to bore them out, which would then reduce the structural integrity of the frame. The 1000's radiator is larger (and needed - you couldn't run it with the 600's rad) and therefore likely to be hit by front forks under braking.
I suspect the basic steel frame & aluminium swingarm would be very borderline at coping with all the extra power and torque and the standard forks can't even cope with the standard bike's performance.
...but if you do decide to go for it, and have very deep pockets, keep us all in the loop
Personally, I'd have considered 660/695cc big bore options for the standard engine: that would provide a more realistic boost for the chassis. Or just go nitrous and get a heavy duty clutch fitted. Or just buy the 1000