I also have very short legs...maybe a little under 28 inches. I found the Cannondale WSD 44cm fits me quite well with 650c wheels. It seems to have a little more length in the cockpit than the Trek did.

I had even fewer choices in finding a mountain bike that fit me. The only one I found that gave me a couple of inches of standover height was a Gary Fisher Big Sur GS extra small. I am happy with both bikes. Fewer choices made the decision-making process easier!