Yo!
Boy, you really do have a tough one. If I were sitting in front of the
drive, it can be done with careful use of DISKED or some other disk scan
utility. At this point in time it looks like you may no longer have the
format information. The approach I would take to it might be to guess at
where the partitions are and then change the RDB until it is recognizable.
If you find the root block (not too bad to do in fact), you can calculate
what the partition sizes should be. You should be able to hack up some
code that scans all blocks on the disk looking for root blocks. If you need
help with this, I can try and find some sample code lying around.