I found rumors about a drop-in CPU replacement version of the Xeon Phi, but did not find anything official regarding release dates, technical specs, hardware or OS compatibility etc. Could be a very interesting chip, although likely to be priced outside my range lol.

Modifying code to run on Xeon Phi is supposed to be a lot easier than adapting it for GPU. Sounds like a challenge to me, but I do not have the resources to play with, nor indeed the time available right now.