Apple is only interested in only Cleaner 6, not Combustion or 3d Studio Max.
Cleaner 6 is an essential app for professional video editing people. However ever since Discreet bought it out they let the Mac version somewhat rot. They omit features in the Mac version compared in their windows version, and so on. Since Apple wants to maintain their market share in the video editing community, they would probably purchase this app and integrate it into Compressor. Compressor is apple version of transcoder, but it is much less sophisticated than Cleaner is.
This rumor started at Apple Insider
http://www.appleinsider.com/news.php?id=264
While they have a pretty good track record, I believe that they are wrong about this.
Why would Discreet sell its best selling product, unless they were near bankruptcy (which I highly doubt). However I have heard that they are in a restructure phase though.
Even if there was the slightest chance that Apple bought 3d Studio Max, I believe that they would still donate it to FIRST. They donated File Maker Pro last year.