DCamProf is coming out with a GUI I read on that post in a month or so, so that may well be an option too.
Yep, it's out now known as "Lumariver Profile Designer" and has built-in support for ColorChecker SG, including using the white patches for automatic flat-field correction:
Presentation here:
http://www.lumariver.com/#LumariverPDYou can make single or dual-illuminant DNG profiles (DCP), or ICC profiles, including those with special curve encoding like Capture One has.
Do note though that as the CCSG is a semi-glossy target it's difficult to shoot without glare issues. I'd say that studio conditions with a careful lighting setup is almost required. One could try the trick described here to make an outdoor shot with a glossy target:
http://www.ludd.ltu.se/~torger/photography/camera-profiling.html#step3_outdoorbut I would myself go for an indoor setup whenever possible. That said I haven't actually tried shooting the CCSG in such a black-cloth-on-cardboard box setup, maybe it works out really well, it would be interesting to try out sometime.
If you're making a general-purpose profile rather than a reproduction (copy artwork etc) I think a target like the ColorChecker Passport is just fine. The quality of a general purpose profile is less about precise color matching of high saturation colors and more about tone reproduction. It doesn't hurt to use a CCSG though, assuming that you make a good target shot with minimized glare.