Okay just when I thought I would put the Haswell in the server and run Win7, I stumbled across SVP! In order to run SVP you need a strong CPU in your HTPC. So my new plan:
Buy Haswell i7-4770, MoBo and $150ish GPU for HTPC.
Move i3-2100 and MoBo to the server.
This should allow the HTPC to run SVP and my extenders will still be "attached" to the HTPC and not the server.
So only question now is WHS2011 or Win7 64-bit for the server OS?
I have to return some video tapes....