Multiple tables/arms are for poor people really. If you are not one of them just get something like Continuum table with Cobra arm with one of those $10k cartridges available and be happy with it. But for most of us it does sometimes make sense. Personally I wouldn't need two tables but I might want two arms/cartridges.
Multiple turntables
To those of you who have and use multiple turntables, how do you hook them to your system and what sort of stand or support do you use. I use different phono preamps running into an integrated amp, so each input is a different turntable/arm/cartridge combo. Others may use phono preamps that accept more than one turntable input. However, mounting multiple turntables have been somewhat of a challenge, since they take up a lot of room, must be accessible from the top and need a solid support. Anyone use a pull out shelf system?