My Network is something like
Cable Modem->Linksys WRT54GS with sporadically connected WiFi devices and hard-wired Media PC->Home Plug->Mains Wiring->Home Plug->Switch with 2 PCs, Laptop, XBox 360 and PS3->CAT5 through the ceilling into next room->Switch with 2PCs, VOIP Phone, PS3
So yes I think your scenario will work