Just to let people know, because we all like decent free stuff, that a free version of the Jamstix drum kit software is available for download.
I found it a bit fiddly figuring out how to get it going, but it sounds pretty good.
To get this software going, you need to click on the 'Load' button and select one of the kits presented in white letters, which are the only ones available for use in this free version.
Alas, I've so far found two important features disabled, ie. the option to save the kit, and the multi-output routing.