If I'm understanding right, you're wanting to put together a chart which has all of the colours of the packers which are available right now (or at least most of them?) The problem with doing something like this, unless you own all of the packers yourself in all of their colours variants, is that you'll need people to send you the photographs of their own packers. People sending the photographs will have to make sure that the white balance on their camera is set up correctly, and that their packer hasn't been discoloured from being worn. Then when viewing the colour charts on screen, if your computer monitors colours aren't calibrated properly (and lets be honest, how many people actually bother to calibrate their screens) then there could be problems, although in the majority of cases not major ones. Bigger problems happen with laptop screens as the colour changes from the angle you're viewing them at. As for printing the pictures they would then need to be checked against some items to make sure that the printer is printing them at the same colours they should be.
It's possible, and would be a really useful bit of information, but a bit of a challenge to do, and would rely on the photographs you're being sent having good quality lighting, colour and the correct white balance. If you're that fussy about it then you'd have to limit the camera being used to those you can preset the WB, so that's camera phones and some compact digital cameras out of the question.
Probably the best way to do it would be to ask for photographs of new, or at least ones that haven't been discoloured, packers on the smoothest part of them so shadows don't affect it (for example on the flat back of the Mr Limpy) and give a list of things that need to be done when taking the photograph like flat lighting and good WB. Instead of comparing the colours to common or similar objects I think I'd find it more helpful if there were as just strips of blocks of colour (like the colour strips you get when you go to buy paint for your house). So you could have a set of all the Mr Limpy colour variations, the GVs ones, and then maybe arrange them in skin tone ranges so people can see which of the "vanilla" or "caramel" coded products would suit them the best.