I manually installed 2.1 which was leaked by Acer to the public (also installed an Eclair custom rom on top). For the most part, it has been stable (did have a couple of freezes but stable for the most part. Also the Liquid E released yesterday and that has 2.1 native so expecting Acer to release the official update soon).
Also a few people in the dev community working on FroYo.
Black AT&T Motorola Atrix 4G
ROM: CM10 by Epinter
White Acer Liquid A1
ROM: LiquidNext 1.9.2 @ 998MHz by Suxsem, ThePasto