I would have to say not very many! I too have done an exhausting search into this after I changed my K frame to a tubular version and noticed all the room available to me now. With all the manufacturers out there the only type available with a hi-capacity and low profile was only with the rack and pinion steering option which was $$$$$$$$$. so back to the 7" deep pan and drag link set up.
If you find something let me know!