Been looking at Mistika lately - cool for grading & working with Stereoscopic 3D images (but not cool for editing or audio as far as I can see).
Has 2 very sensible rendering features...
1. it stores a small sidecar metadata file when rendering - which is effectively a subsequence of the section that is rendered. Same name as render file but different extension.
2. the render media file is placed on the timeline vertically above that which was rendered (much as a video mixdown can be edited onto the higher track in Avid).
Would be very helpful for Avid to do the second when doing a video mixdown. (Especially if Send to Playback could then also realise it no longer needs to render all the tracks underneath this fully opaque bit of media).
also MambaFX looks an interesting & cheap offering from SGO - v. similar to Combustion in it's offerings,easier to use than Fusion & could be quite a nice addition to Avid editorial. Only Windows or Linux though.