Zope3 as Zope2 Product?

After I read about the ArsDigita Experience (TM), it occurs to me to ask:
can we look at Zope3 as a Very Large extension to Zope2?  They're both
still zodb based and there's likely to be some name collision issues,
but I suspect that it might be possible to (for instance) add a Zope3
folder which would direct requests to the Z3 engine while all other
request would go to the Z2 handler.  Since they're sharing the same
object space, it would be possible to slowly migrate applications over
to the new system; a database adapter is still a database adapter.

First Big Issues (off the top of my head).
  o Python versions 
  o Stability / testing (Z3 might only be as stable as Z2).
  o Security / users / naming integration.
  o Acquisition zig-zags 
  o zodb versions?
  o Search engine integration

What this says is that the immediate Z2 action is to make the conversion
up to python 2.2/2.3.

Thoughts?

Gary Godfrey
Austin, TX USA