I have an SX1272 based gateway operational, as proof-of-concept. It works well, also with the current TTN back-end.
This kind of gateway is great for experimentation, and to fill the time gap until the TTN kickstarter gateway will become available. It would not be so great though if this gateway would be deployed for permanent usage, it kind of breaks the LoRaWAN model.
There is a bit more work todo, but I will make it available publicly.