Hi, I found a new version of the txtreader on gemeitech forums. Its called 'unnoficcial' so I wonder If there is an sdk on some place...
Here is a mediafire link.http://www.mediafire.com/download.php?tdmi4jyizdy
You have to copy the .sim on the emulators path, with the other .sim files, and the folder on same path, and open the files using the 'interesting game' menu, same way as emulators.
It supports only txt, but lets you select the font (ttf) and has more options than the regular txtreader. And you can have both on the player, one on emulators folder and the other on the menu.