Yes, I'd imagine that 10/100 Ethernet networks would be OK with higher video streaming. We haven't done enough testing to be confident of this, and you should keep in mind that the cheap router you get with a tank of gas

these days may not REALLY be able to keep sustained 80 Mbps going through it. For most people's web browsing needs at home, nobody's going to notice.
The hardware design of the current models absolutely, 100%, prevents them from delivering HD output format.
As far as the "HD" in the name of the product, I have to consider that creative marketing. You can connect the box to an HD source. The specs on the website are accurate if somewhat dense. Our main competitor, what's their names, Bling, Fling, I can't remember, also claim "HD compatible" on their higher end product and it is essentially the same story (so far).