http://www.virtualmechanics.com/products/dwarf/
Not much info on it but here are Amazon reviews of their paid version
http://www.amazon.com/Virtual-Mechanics-SiteSpinner/product-reviews/B000AOJOUI/ref=cm_cr_pr_top_recent?ie=UTF8&showViewpoints=0&sortBy=bySubmissionDateDescending
Installation isn't terrible, but does add a couple of Microsoft C/C++ runtimes resulting in a recorded 2400 new registry entries, which is a bit more than usual but not *that* bad for apps that add the runtimes.