To be commercially successfull it needs some flavour of android.
It might still be interesting to keep foucs on providing well documented hardware. Gta04 for example has documentation for all interfaces except UMTS modem, the WiFi module and the GPS module. If it's well documented standard linux (Debian) could easily later by the community be provided.
It for me looks like Linux can run on Qualcomm SOC (not sure exactly how well it does, e.g. with current kernels).
Is it possible to use a (second?) modem Gemalto PLS-8? It on the one hand would raise the price, but might be better supported by Linux.