I was on a quest also to solve the "hot corners" problem and came across your blog. I tried to post back to that, but couldn't figure out how to... oh well. I finally found a reliable, free (both in cost and virus content) solution. It was on the ZDNet site so it should be reputable. Here is the link:
The site will make you register to download the utility, but registratoin and the utility are free. I use bugmenot for these situations and it had a working UID/Pwd. If you aren't familiar with that little gem, google it and get the details.
I was like you and could not believe that someone wanted to charge $12 for a utility to do this... hopefully no one has paid that fee yet!