Hey Andy,
Nice system! I've always admired the Beolab 4500's. The two Beograms, with built in pre-amps, that will work with your system are the Beogram 7000 and 4500.
Tommy
Edit: Sorry, forgot to add the Beogram 6500 as well. If your not familiar with these tables, they are all essentially "mechanically" the same turntable (tangential). They really vary only in cosmetics, with the 4500 table matching the rest of the Beosystem 4500, and the 6500 and 7000 matching the Beosystems 6500 and 7000 respectively.