I have a Zenith medium sized antenna on the roof with a rotor and an amplifier - can't remember the model #. It's probably equivalent to Daves's VR75. The amplifier actually made a big difference as I have a fairly long cable run. I have a Sony HD100 and get all Balt stations in the 90s. When I rotate I can also get the Washington stations in the 80s. There is one spot where I can get them all together, but even though the signal strength is decent for all, in the 70s, the signal is prone to break up for all kinds of reasons, like a plane going by, etc. So I rotate.
I'm not 100% sure of this, but if you wanted to go the 2 seperate antennas pointing in different directions and only have the one cable run, I believe that you could use a combiner (a splitter, used in reverse basically) to place them on the same cable. When I was playing with attic placement this is what someone told me, I abandoned the attic and never tried it, but it might work.