Two important data points;

1) I got non-owners (renters) insurance through Avemco 2 years ago,
but upon reading the fine print, discovered that they DO NOT COVER
experimental aircraft.

2) I switched to Costello because they do, and when I renewed in
January '09 the copy of the policy had an AIG cover, but was
underwritten by National Union Fire Insurance Company of Pittsburgh,
PA (A bit confusing)

Matt