I'm looking to either load balance / failover two webservers which
serve some sites which operate out of access databases. I guess
ideally, both servers would offer webservers and both would act as
database servers with some sort of frequent, bidirectional updating of
the data to keep them in sync. Any good solutions to this?

You could add one more pc and put the access database there on a
share, as always the local network between the two webservers and the
file server sharing the access database has to be absolutely reliable.
You could also look into using MSDE which Microsoft is giving away for
free but has a 5 connection at a time limit which should be no problem
if your application closes connections properly and at the correct
time. Given this scenario you could cluster the two web servers using
the MS Network Load Balancing service or if you want a simpler but a
little bit harder to maintain solution you could go with round robin
dns.

I think this is going to be the answer, which basically amounts to
"use sql on a third machine instead". The attraction of being able to
use Access, however is more the ease of deployment than the cost. If
anyone else has got any bright ideas, that would be very helpful.