http://www.aircraftspruce.com/pages/...lphaJacks4.php
These are probably the most common. If you can find some used you might save a buck or two.
Remember you still need to support the booms. In the SM it only calls for one support but I like both booms supported evenly. These don't have to be hydraulic but it sure make them nice if they are.
I just converted a set of high wing jacks to boom supports. This is really a nice touch but for just using them once a year probably overkill.
The photos show a set of stands that Jerry DeSantis owns, they work well but require some blocks under and lots of lifting as the aircraft raises. The photo of the hydraulic stands are the set I converted from a set of homemade jacks for a Cardinal. The last photo is something I witnessed and it was scary. The single boom stand didn't extend very far so the aircraft was perched at about a 20 degree angle and no jack under the nose. It worked but not in my shop.