I'd like 2-3 more C# settings.I don't have mine yet (it's coming today or tomorrow), but it would be nice to have 5 or 6 C modes and to be able to label them - Studio, Portrait, Landscape, Action, etc. Okay I guess that sounds like the icons on the Rebel mode dial now that I type it, but you know what I mean.
Unfortunately, more C# settings can't be added in firmware, because there are only three Cn
'lights' in the viewfinder display. What they could do on the 1D X, though, is provide the ability to switch the base mode of a C# setting (Av to M, etc.) without having to recreate the whole setting.
Having said that, I do basically what you're looking for in a different way. I have 'groups' of C# settings - a group for general use (C1 for tripod with MLU+timer, C2 for 'static' people with a 1/125 min shutter, C3 for moving people with a 1/500 min shutter), a set appropriate for birds (Av and a slower shutter for perched, M and a fast shutter for BIF, M with flash settings for using the Better Beamer in the three C# settings), another group for sports, a group for landscapes (an HDR setting, etc.), and a couple others. The 1-series bodies allow you to save/load settings to/from a card, and I keep all the groups on a few old (smaller) CF cards in the BR strap and in some camera bags, then I can load the set appropraiate for what I'm shooting. So in a way, I have about 18 C# modes that I use.
I set the M.Fn button (next to the shutter) to switch modes - that cycles between the last-used regular mode (Av, Tv, M) and the C# settings. C# settings that won't be used can be restricted so you don't cycle through them (I turn off C1/tripod for general use, for example, because if I'm setting up on a tripod I have time to enable the mode). Makes it very fast to switch between modes.