I agree with you 100%. I did not become aware of any Thecus-made modules until one of my site visitors from Australia sent me the module files. My guess for the reason why Thecus does not officially make them publicly available is that Thecus does not want to deal with supporting them. Of course, they could have easily added a disclaimer (like the one you have on your site ) about the use of the modules.
Other than the P2P-BT and the PPP-BLOG modules, i am not aware of any other Thecus-made modules.