mITX FM1 boards aren't cheap
If its wireless N then you can do it, but you may notice that occasionally your films will start to buffer if the signal drops.
I would go powerline before wireless.
That has an onboard HD 3200 chip so it would easily handle 1080p, the CPU would be doing very little.
Would a normal mini itx board do? I really am trying to do this on a budget.
Powerline seems like a good idea but I have no idea how it works, can you explain please? Also, could you recommend a cheapish half decent powerline?