Well, RGB is fairly good, but I find that you have to use CMYK or Pantone for ensuring totally accurate colors when printing. Even so, the reason that companies don't do as you suggest is because it can be expensive to produce.
I'm working on a DVD project right now and they handed me this really good "style guide" to ensure proper colors were used, along with all sorts of other good information. Let's put it this way, not all of it applied to me, but the parts I needed, it definately made things easier.
My suggestion might be to use photo printing paper for inkject printers. That really seems to help. That and the "photo" ink cartridges. I switched from using regular printable CD's and DVD-R's to disks with a smudge-proof surface and it makes a world of differnce. I don't have a "photo" inkjet cartridge option because of the unit(Primera Bravo), but everything looks better on the smudgeproof discs.
Since you're going to be hopefully doing infrequent one-off prints, the costs should remain relatively affordable. Using the sheet protectors just gives an extra layer of protection.
I would think a batch of "really super common colors" should be sufficient. I'm using R,G,B, light blue, yellow, amber, pink, purple, dark red, dark blue, dark green and some other colors to match the various color wheels. After that, I can go RGB with my gel'ed Par38's and my 64 LED Pros.
I can't give any real guidance as far as colors are concerned. Different places have different idas. Go with the basics, expand from there. Best I can guess. The good thing is that the way you're approaching things, there is no "wrong", just a good reference to get things going quickly.