How much are you willing to spend?
I'm in love with the hoist model:
Because you can do supinate, pronated and neutral grip pull-ups. However, it's not cheap. It's a consumer level piece with commercial quality and pricing.
Also, if you can fit a cage in your space, the Powertec power cage/rack has pull-up bars, dip bars and is a lifting cage/rack all in one for about $299.