If they are "working" on the Game Boy mold to make the Virtual Boy mold, does that mean you will no longer be able to produce GB cases? Is there enough supply to continue to sell GB cases if you can no longer produce them? I don't know how many you are continuing to sell on a regular basis, but I know that I will eventually need more.
I'm surprised there is enough demand to work on Virtual Boy cases right now. Don't get me wrong, I think we would all eventually like cases for each type of cart based game. But I would think we would want to work on the more popular systems first. As seen with the GB cases and NES cases, there is a very long development period for these cases. I can live with these long development periods because I understand that working with overseas companies has its challenges. But if you work on something like Virtual Boy, I would think it would just add more time before we see things like Genesis cases or SNES cases. Just my two cents.
***EDIT***
I forgot to answer your other question about DS cases. While it would be nice to have a source for brand new DS cases, I would consider it to be low priority because there still seems to be a good supply of used DS cases in the market. It's very easy to get used DS cases for around $1 each, shipped. As long as that supply is still good, I wouldn't spend too much time and money developing replacements.