I have also only been involved with the TI community, but I have always been curious about the other calculator communities (Casio, Sharp, HP). I did some cursory research, and it appears that the other calculator communities are quite small in comparison to the TI community and that there is no equivalent wiki community site.
I am not exactly sure how to best organize the different calculator information. Perhaps placing each of the other calculator-based pages in their own calculator namespace is the cleanest way to go — for example, casio:casiocalc.org, hp:hpcalc.org, etc. I could also create a separate Wikidot wiki for each calculator — Casio Story, Sharp Story, HP Story — but I don't think that is really necessary. However, it might be good to register those wikis and redirect them to TI Story just so somebody else can't.