lost system tables: any hope?

I'm one of those people who created the system database on one partition
and put all the application databases on another. The latter was backed
up, but the former was not. And that drive crashed.

What I'm faced with now is the situation where I know that all my data
is still on disk, but the data structures that would let me access it
are lost forever. Even for a single-table database, postgresql (7.1.3 in
my case) creates about six dozen files, all named with numeric values.
I'm not seeing any documentation that would help me figure out what's
what, much less suture the files into a new set of system tables. About
as far as I can get is to run strings on the files and see which contain
what.

Armed with enough time, I'm sure one could reverse-engineer this stuff.
Of course, I'm not armed with enough time- I need to get back on the air
as soon as possible with several of these databases.

Any help out there? I've already figured out that I need a better
disaster recovery strateby for the future; it's the immediate present
that I need help with.