As far as I know, Freescale has no immediate plans to discontinue the 8640, but they did state that the 8610 was going to remain available for several years (making it a better bet for long term production).
Personally, I like the 8640 (as you know Andreas). But its a relatively high cost processor and the only Southbridge chips I could find that would work with it are produced by AMD.
Since you pointed out to me that there have already been posts (on MorphZone) on the recent introduction of the first Titan based Soc, I'm sure you're aware of the advantages of that processor (PCIe 2.0, etc.).

The main problem I see with QorlQ (or Titan or, for that matter, the 8640D) is that they're multicore processor (and, as you've repeatedly pointed out, MorphOS doesn't support SMT). While there are a few single core variants they're still limited in speed (making the multicore variants more attractive - if we could take advantage of them).

Anyway, after spending several months studying the idea of producing a new PPC motherboard, I've just decided to buy an Apple G4. Producing a new board would be quite expensive and except for the ability to use new expansion options (via PCIe), there isn't much of advantage over buying a used Apple (after all, the max clock speed for an 8641 is slower than the max speed I can upgrade a G4 Mac to).

I don't see the point in mortgaging my house to produce something that might not even get supported by MorphOS or AmigaOS.