Since we don't have any GSM Booster Packs available in the store, how about we create one as a team.
We can do a group buy and get SIM900 for about $16 a piece.
I can make PCBs, someone else would take care of the software, assemble the boards for the store, etc.
It would be nice if we could enter the design challenge, but I think we don't have enough time.