To be honest I'm not really sure. If I was to say an arbitrary number like 30 or 50, that isn't even enough to make it affordable for everyone, yet only a fraction of group buy participants actually show up in interest check threads. Basically anything where the interest accumulates quickly and the thread stays on top of the section. If you were to go about posting it you can send me a PM and I can contribute my input/info.
Note* I'm assuming that because you're relatively new some of the following may not make sense, so let me know if you need clarification on anything.
If we were to do a rerun, I've gotten permission from 7bit to use his custom legends, so it would be different from the 2.0/Klaxon, and much closer to the original Red Alert. I'm thinking that's something a lot of people would be interested in. Also I would run it exactly the same way I ran the last one, since I would want it to be the same custom colors I picked out... the new ordering system that some organizers are using doesn't apply to colors outside the limited set that they have for that system... however comparing prices between Klaxon and this group buy, the prices should still be cheaper if we merit enough orders.
Also, you can certainly throw up a WTB thread in the classifieds if you haven't. Not sure if you need more posts to do that, but expect sellers to ask for a gifted payment on your end since you have no reputation.