There is no difference other than the paint scheme. I am building up an IAxx and wanted the frame only, and personally preferred the colors of the IA16 v the IA10. Speak with a LBS, as they may be willing to part you out an IA16 frame. Alternatively if you want to do the work, you can get the IA16 and sell off the other parts on your own. I lucked out as a forum member bought an IA16, parted it out and then decided not to build the bike so I was able to get the new frameset only easily. TriRig AlphaX, OmegaXs, my PM and groupo - it's going to end up being a very fast bike. Cable routing this weekend. My first time building a bike, and it has been much easier than I expected.

Sorry, I can't speak to EU.

Good luck on the search.