Hi10P (also called "10-bit") is a profile of the h.264 video codec. It has recently become popular in the anime scene for video encodes. The current stable release of XBMC (v11 "Eden") does not support the h.264 Hi10P profile, but current development builds do (Pre-v12 "Frodo").
The first stable version with Hi10P support is planned to be XBMC v12 (Frodo).
1 Hardware requirements
Hi10P won't work on ARM or even Intel ATOM processors (maybe one day, but none of the current ones in 2012 would do it). Hi10P can't be hardware decoded (which is to say, no one makes hardware decoders for them and no company plans to add Hi10P hardware decoding in the foreseeable future), which is what Raspberry-Pi, Android, ATOM processors, and some AMD APU systems require for playback smooth demanding video (Hi10P is very demanding). Thus, Hi10P requires CPU/software decoding.
A safe bet would be at least a core2duo processor (or equivalent AMD) or higher.