Try US Jack. They have the 3 ton and 6 ton units on sale. I bought a pair of the 3 ton and they're very well made. In the USA.
http://www.usjack.com/products.html
I also have 2 pairs of 3 ton, and another 2 pairs of 6 ton stands from the US Jack. They are awesome and well-made. I highly recommend them.
