Many people have tried this and many have failed.
I remember one such venture that someone advertised several months ago on this board.
I pointed out to them that it would never work for various reasons including the ones mentioned above. They not only got very angry with me but informed me that they had already invested a great deal of money/equipment/time into the project without asking the community what they think. Needless to say they weren't very successful as I've only heard tale of them selling one of their prototype cabs towards the initial startup.
This isn't a case of me saying I told you so to those guys, but of me trying to keep you from starting a bad business.
Here's some reason's why it wont' work......
#1 Cabs are too darn heavy to ship...
#2 No one is going to pay for cabinet plans unless they are the best darn plans in the world. They're are way too many free plans out thee already and the community is very open to sharing how they did things.
#3 This is build your own arcade controls not buy them...
I know what your thinking on that one so let me explain. The general mame public doesn't really respect the original arcade feel and are perfectly happy to play pacman on their computer with their joystick. We arcade control loving guys are a very small part of that market. Also the few people that do buy pre built control panels aren't necessarily interested in a full cab for both monetary and space reasons. So you take taht number and cut it down again. When you get down to it there's just not enough people out there. But just for arguments sake I'll go on.
#4 The public is very demanding. .... Your not going to get away with cutting out lumber in your garage and screwing it together unless your a master carpenter or have several 1000$ worth of tools to help you. A simple plywood shell proabably wouldn't go, it would have to be laminate and /or a very good design at that. Like this:
http://www.cybertechdesign.net/mameroom/ultimatearcadeII/day15.htm #5 DIY means generic and the majority of us each want something different.... You'll notice that the cabs cyberpunk built were basically made to order. It took him several months and alot of hard work just to produce those two cabs btw. And from what I understand the buyer didn't want to fool with assembly. Which brings me back to what I said earlier, those who are too lazy to build/convert their own cab generally don't want to fool with assembly either.
#6 What would your kit have that makes it special? It's the first rule of marketing. Just because you build it doesn't mean they'll come. Are you going to have special retainters/ bezels/ ect made for your kit? If so are they going to be as good a quality as happs stuff? Also if your kit merely consits of the cut out pieces, that is by far the easiest part of the cab. If your design is simple enough 90% of the cuts can be done for free in the lumber yard. Some even cut laminated panels now (although i'll admit that's rare)
Ok I'm done.... Once again I'm not trying to be a jerk, I'm just stating the obvious to help you make your decision. Remember 75% of all small businesses fail in the first year. With the current world events I think that ratio is even higher right now. (But 75% is the given business rule of thumb)
Remember:
No project is a small project.
No business that produces a product has small start-up costs.
No un-tested market is without a great deal of risk.
My finance teacher would be so proud.