If you are really intent on finding all versions, you could try looking at the TOSEC dat files; they may contain info about versions that you haven't found yet. The RomCenter ones are the most human-readable IIRC.
Also, if you run the disks you download through ClrMamePro or similar, you will be able to find out exactly what you have without waiting for people to upload your requests. You might even find versions that aren't in the dat file or that are quite rare on the net. Certainly I haven't seen many of the update disks around (as opposed to the full version) for example. Then you could contribute something whilst still completing your Sensi Soccer collection
