I'm sorry, but this piece of software so deeply hacks the Mac OS X interface, I'm going to have to pass.
You (the developer) will need to back up these hacks with solid (test proven) claims that it doesn't bork your system so badly that you get kernel panics or weird/odd behaviour.
How does this affect getting tech support from companies who write software for Mac OS X? I bet if you mention that you've installed this hack, a 3rd party developer (or even Apple itself) would be very unwilling to help you get past whatever bug you think you've encountered with their software.
The lengthy list of known bugs (http://www.ocs.cz/OCSmartHacks/KnownBugs.html) doesn't help me feel any better about this either.
If you are going to charge $29, a 30 day money back guarantee would be good too, to make sure that this software works in conjunction with all the other software that a person has installed on their system.