today i dumped the system-rom of the german equivalent, which is called "MisterX" and was distributed by YENO.
i also got the cartridge "Fantasie Trivia", which i dumped too. as with most cartridges for VTech/Yeno consoles, this cartridge-rom also contains the data of two different cartridges. a fix soldered jumper on the cartridge-pcb selects the first or second half of the rom. good for us, so we got two cartridges for the price of one! ;-)
the system uses a TMPZ84C00AP, which should it make easier to get the system emulated! so hopefully someone is interested in adding the dumps to MESS.