I've tested the UT2004 no-cd patch from GameCopyWorld, and it works great. Just rename your old .exe to .exe.bak and then keep it for when the game has a patch, then just rename the 'patched' exe to .exe.nocd and rename the original back to .exe then apply the patch. A couple days after the patch, the no-cd patch will come out and then just do the same thing with the new 1.1 version as you did with 1.0.
But, I do agree, being able to use the ISO instead of messing with the exes is always better.
Dave