OK, I have just pushed an alternative solution to the module dependency bug, this one (I believe) only triggered by INTRA-system dependencies. This one is also on the module-depends branch.
This was achieved, as I said, at the cost of some hair, but I believe it does the right thing to the extent that I understand the right thing, and thinking about James's email convinced me that I /don't/ understand what is the right thing with respect to inter-system dependencies.
Somewhat disappointingly, this commit agrees with the last one on the tests, which indicates that the tests need to be augmented...
Additional reviews very welcome as are test results!
[Fare: is your XCVB going to handle the kinds of inter-system issues I raised in my earlier email?]
Feeling like Richard III, I can only say "A spec! A spec! My kingdom for a spec!"
Cheers, r