Came across this website after purchasing a WSM from Cabella's for $195 (could not resist the deal) and I was looking for a cart for it. Found a great post on the site (http://weberkettleclub.com/forums/wsm-weber-smokey-mountain/my-diy-wsm-cart/
) and have been reading many other posts since then. I attempted to build my version of the same cart and it turned out pretty well. The only issue has been accessing the side door, but honestly I only open it to stir up the coals.
I also have a Weber Genesis E-330 that I bought on Craigslist which required new grates, flavorizer bars, and a good cleaning. Works like a champ.
Here is a photo of the WSM in the homemade cart. I added a hook on the side which does a great job of holding the dome. Also, I am not much of a wood worker but this was a relatively simple build and I highly recommend it.