As of v2, or so, MAME now supports MyArc Extended BASIC II. I had this on PC99 and really liked it. It uses the MyArc memory card and disk/hd card. the XBII is fantastic. it's much faster that TI XB, sometimes up to twice as fast. It has a whooping 72k of program space and accesses all the graphic capabilities of the TI VDP such as 40 cloumn, hi rez, all the sprites and added character sets.  below I have set up a zip file that has all you need to run MyXBII. you just add the latest MAME or