Apparently one of the test/futures/demo motor Aerotech has is the J99N endburner. I first found out about it here on TRF, where an AT rep says it has a 10-second burn time - one of the longest burn times available in any motor.
Some info on a test flight can be found here.
Here Gary Baumann notes that it's for 54/1280 hardware.
Update: certified on 10/26/09; full info here, and it's actually for the 54/852 hardware.
Launch Report 2017-2 - LDRS-36
2 weeks ago