Repository collection practices

[Mark White]

Out of interest: what kind of working practices do people
have for organising their collections of Hg repositories
(which, under eg Subversion, might live in a single tree?)

And am I right in thinking that the revlog approach to
hashing changes means Mercurial is fundamentally not geared
to work with subtrees?  (In other words: is it feasible that
"hg clone" could work on part of the tree one day, without
breaking the ability to push/pull between clone and parent?)

Mark <><