Now that I've figured out how to make a Premiere plug-in, someone suggested I add JPEG 2000 support to that program as well. Good idea. So that's what's new in j2k 2.7: a plug-in for Premiere Pro and Media Encoder. Just like in After Effects, the Premiere plug-in supports auto-proxy, so working at a lower resolution in Premiere can dramatically speed up frame load times. It also supports the choose-your-own bit depth and DCI features found in Photoshop and AE.
There are a few other optimizations and minor bug fixes for the other plug-ins too, so everyone should update. Yes, it's free. Enjoy!