Pretty sure.. hang on... hmm... can't see anything off hand. However, I clearly remember there being something somewhere for it. I suspect it may be as simple as just switching the crystal and CPU, but I'm not sure.. that should stick it up to 14MHz though I think.
The best thing you can get for a bridgeboard like you have is a multi-purpose card - they do exist, with serial (you need this if you want the best mouse handling - don't need a mouse card), parallel, VGA, sound (I think), floppy, hard disk.. you name it. They're pretty scarce though from what I recall, but dead useful for saving on ISA/Zorro slots! I suspect if you're short of anything, eBay is your friend!
Be warned, though, the 286 has no concept whatsoever of 'plug-n-play' so be prepared for some fun IRQ/base address handling!