GHI will continue in supporting the community in making more gadgeteer modules. We started by promoting the community wiki and we want to help with sockets.
Stop looking for cheap gadgeteer-sockets, we got them for you at $0.50 each. These are SMT but if you bend the pins out then they are TH-ish. We know 800 maybe too many bu you can always buy a reel with someone else and split it. In my opinion, if you make a nice module (and most already are) you will sell 800 in few months.
Hopefully we can install a second line and even manufacture your modules in future