The problem is that almost all wheels that can handle that kind of abuse are for disc brakes only.
Sun Rhino Lites are beefy and for rim brakes. You can get the rim for around $30, but then you have to have it built up. Complete wheelsets can be found in the low $100's, depending on what you want for hub options. It's cheaper than the outlaw and a bit lighter.
http://www.bicyclewheelwarehouse.com/index.php?act=viewProd&productId=35
I have a front wheel that you can use. It's not super beef, but it's gotta be better than the rim that came on your bike.