Looks like this thread was written a number of years ago, but this may be useful for any future readers... OMNI Mfg. sells cultipackers with a very simple, but strong design. They are well built all around. Also, they use ductile iron wheels (vs. regular grey iron). The reason for this being, ductile iron has 300% more tensile strength than grey iron. This is a quality, affordable product & I speak from experience. Check out their website...

http://omni-mfg.com/Cultipackers-C110177.aspx?sid=10512