I used to own one of those. I think it may have been used in convenient stores like Seven-Eleven for POS things here in Japan at one point, if I'm not mistaken. I bought it in Akihabara circa 2007.
Please don't forget to mark compatibility in the SCL for apps that you find do work (and do not work!) as it will make it easier for others to find them!
@CE Geek perhaps you could do it for your known working apps too. I've added the few from the link for the Aero, but more votes is more better and I've not done any other SH4 devices.