If you set up a custom paper in the Color Center, you are not REQUIRED to create a custom ICC profile for it. Based on the media type you choose when you create the custom paper, the Color Center will create a "generic" profile for that paper. Once you create your own profile (using the embedded system or external packages) this is added to the mix. So yes, you could have several profiles for each custom paper you create.
For example, if you create a custom paper for Moab Entrada, and you choose Fine Art Paper as the "starting point", the Color Center will associate its generic Fine Art Paper profile with that custom media type. Unless of course you create your own!
Hope this helps...
Eric Bullock
Mac Business Solutions