Being optimistic, with somewhere in the region of 4000 empegs out there, you'd hope that the market would be bigger. Being realistic, only a small percentage of owners are regulars here and thus actually now about the button hack.

I don't know whether that 200 figure is accurate or not. Perhaps over time 500 would be reasonable. I do know that I wouldn't want my money tied up in 500 kits hoping. Since the biggest cost in low volume injection molding is the mold itself, I wonder if a better value proposition would be to offer (eg) 125 sets of all 4 colors for $60. This would appeal to many people and help recoup costs faster.

That all being said, Eutronix are making a concerted effort and have made an investment that they want to recoup, and it looks like Brian might be back in the game too. I wouldn't be comfortable making a $500 investment just to go into competition with those two - one pioneered this hack, and the other is fast gaining an excellent reputation as a one-stop empeg service shop. Tough competition.