There is not enough "market" for Cisco to R&D a stratum 1 module.
It is better to get a GPS-based stratum 1 appliance elsewhere. Otherwise, one can use a pair of Linux servers to act as a stratum 2 appliance. Better yet, Linux boxes can be hosted on a Raspberry Pi or Beagle Bone units. Either one can be powered up using the USB ports. We have a few in our DC and they're being powered using the USB ports of the HP servers. Works very well!
Read this: Raspberry Pi as a Stratum 1 NTP server & Quick start NTP on the Raspberry Pi
The beauty of the Raspberry Pi setup are:
1. Components are inexpensive (main component cost <US$100 plus extra for the NTP board); and
2. Open source