"Does any one know if ikelite is coming out with a housing for the Nikon D100 or the Fuji S2?"
D100 is on their hot list. S2 housing is a sure thing. Niether is close to release.
"Does any one know if there any way to modify a F80 housing to fit the D100 ro the S2?"
No. While the basic SLR is based on the N80, everything will be changed slightly, moreso on the D100 than the S2. Digital requires a lot more through the case controls.
"Have the camera but can't dive it it yet. Hope someone come out with the housing before the camera goes outdated."
Which one? I assume the D100, since the S2 hasn't shipped. How's it work?
Digital SLR's have a longer life span than the prosumer cameras. Plus, we are getting to the point where new models are more evolutionary than revolutionary. These new 6mp cameras may be all you ever need.