how do I commit somewhere other than onto a tip?

[Vincent Broman]

I think I need the capability to commit versions that are not
successors of a tip revision, e.g. I want to commit a new version
which should be placed in between two successive versions already committed,
or else to place it ahead of all the other versions, as a new version 1.
It might even be a new branch off some parent version in the past.

Why? I have inherited a piece of software to maintain for which I
have found many tens of copies of the source in various stages of development,
stored in separate directory trees on various machines or backups.
From file modtimes and from looking at diffs, I have an
approximate idea of the order they should appear in history.
I would like to get everything into a version control system, to document it,
but I cannot just start with the earliest and try to retrace everything
from the big bang to the present in order.

As I go through I may change my mind as to the dependencies/order.
I may find an additional version on a dusty backup after I have started. 
I may only have time to process the last 10-15 versions right now, 
then add in the other older versions as I have time to analyze them later.

My basic problem is recording history retrospectively, instead of
as it happens.  Is this possible in Bazaar?
I do not like the idea of writing code to do surgery on archives
in ways they were not designed to allow, but concatenating dump files
is something subversion sort-of allows.

Vincent Broman
SpaWar Systems Center - Pacific