The fastest bridge boards only feature a 486slc - a 386SX style CPU with 486 command set. Very slow imho.
Anyone who wants one is welcome to an old Pentium 200 that we don't use anymore. Runs circles around any existing '060 setup, let alone an emulated x86 on 68k.
I've had a 486DX100 single board PC lying around for a couple of years for putting into my A3000 - never really saw the point however and still fail to see it, when something you pick up for $5 at a yard sale is several times faster...