Frankly I don't understand the need of an exe installer... Why don't you use Winzip ?? The size/time argument doesn't stand, you CAN make zips with *just* the modified files since Last Version, and you also can make autoextracting .exe files out of a zip file for the illiterate
If you've a bandwith problem for uploading I can help, I have DSL and a lot of wab space if you need hosting "work" files instead of mailing them from member to member (or using that awful "mod forum" that messes all files with Posts and silly numbers instead of names
).
Drop me a mail if interested