Cell-based OOB management devices

I would look into Uplogix. I've seen them demo their products at Cisco Live a couple of times and they seem very good.
- You can connect a cellular modem to them.
- They can store backup device configs.
- They can store IOS images.
- They can even xmodem an image to a device if it gets stuck in ROMMON.
- Some of this can even be automated by their device.