Nope, the Oppos only upconvert via HDMI also (981 doesn't even have component out)
I have only seen the 971H upconvert and I thought it looked pretty darn good. Since these players are so highly rated as well, I don't think you will find ANY 480p player that will look better than them, period. As for other players, it is hard to say. My Denon is 480p only and I am still quite happy with the picture it presents.
For a quick and dirty answer, I'd pick up an inexpensive HDMI cable, hook up your player direct to the TV with HDMI and compare it for yourself. If it doesn't look better to you then you don't need to run the cable in the wall. Going forward, I would say it is worth while to have that cable there.