Sorry you missed it, we had a Beaver at an old shop I worked at, and it was a durable machine. (and for $75 I would have grabbed it up, no wonder it was gone!)
As to the height, it's up to really what you're using it for. Small stuff that takes precision drilling, then yes, it's not only doable, but preferred to have it "up there", tho changing belt speeds may take a ladder. If you're doing any heavy material work, then you want it further down. (You could build a separate lower bench for the unit...)
Good luck on the next one!