porting a FMPro db to Sybase or Oracle

Hi folx, we're running a moderately complicated set of linked databases that we implemented in FileMaker Pro 3.0 on a mac because of the ease of setup/use. Now we're finding that we're just plain outgrowing the platform, and we long for the stability/speed of a UNIX based system, like Oracle or Sybase, depending on which one will be the easiest to port our existing db to.

Does anyone out there have experience doing such a port, and are there tools to ease the transition? We've heard that there are ways to make FMPro sit on top of something like SQL Server such as to preserve the GUI everyone here is loudly defending, and maintain some of the logic on the mac side, while moving all the data (and all the hard work) to the UNIX server. Anyone worked with such a system?

Thanks for your advice...

                           ....Keith Allen