It could be done, maybe...I plan to try it next year (after I buy a new computer).
Step 1) Create custom case for Rev B (not an all-in-one design. I will use an external monitor)
Step 2) Attach the Mezzanine plug to the motherboard
Step 3) Attach the PCI adapter
Step 4) Run a ribbon cable to the T35 Expander PCI card (in its own box)
Step 5) Attach T35 Split Bridge cable to PCI card
Step 6) Attach PCI Firewire card, et al. (Hopefully

)
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"Life cannot be contained...Life finds a way."
-Ian Malcom, Jurassic Park (movie version)