I am using a Pi in my bedroom streaming from my solo2 and i run hd no problem.
I'm using a Edimax EW-7811UN wifi dongle to connect to my network and it works flawlessly.
I have tried other wifi dongles but the edimax is the only one I found that works streaming full hd.
Oh and also make sure your using the newest version of openelec as raspbmc wouldn't work in hd for me too.
I hope that helps somewhat with your quest buddy