If you can do a 600, congra first.
Maybe you can get a Via pro 133A chipset based mainboards.
It is not yet out as the chipset is just annouced, but it will support 4x AGP at 133 with a 1/2 multipler. Hence your card will work at 66mhz.
The performance is at least going to be comparable to BX boards, but memory bandwidth may sucks with the original VIA pro 133, just with the AGP 4x.