I'd forgo the bridge board and second PCMCIA HDSP card IMNSHO. Try to keep the "Standalone" Multiface powered on, and it will retain its settings until it eventually loses power. Re-configuring the "standalone" MF and re-connecting the primary MF takes a minute or less (save a Totalmix preset for the extra MF ). NTM, the secondary MF and the PCMCIA-to-PCI adapter card will still be detected under RME's unified driver - so if the bridge card has any issues you can bank on those issues having a detrimental effect on overall system performance.
I tried one of those PCI-to-PCMCIA cards with an RME PCMCIA HDSP card, and while I got it to work, the system's ASIO latency performance and scaling was horrible compared to the same PC with the native PCI HDSP card. I'm sure there are some bridge boards that offer acceptable performance, but the small trade-off of potential issues to convenience-factor are nil IMO - so why risk the performance and cost penalties when the time penalty is relatively small?
However, A UPS would be a good idea IMO (always a good idea!)
MADIface-XT+ARC / 3x HDSP MADI / ADI648
2x SSL Alphalink MADI AX
2x Multiface / 2x Digiface /2x ADI8