Acer A100 and A500 may get ICS in January 20121
Apparently, word leaked from Acer Poland that the ICONIA TAB A100/101 and A500/501 would not be getting the update this year, but users should expect the ICS treatment in mid-January 2012. This seems to match up with a lot of the other update announcements that we've heard from other companies, so although there has been no official announcement, there is also no reason to be skeptical.
Acer has been quick with updates in the past, so it seems reasonable that it would be able to get this one out fairly soon as well.
source: Tablet Online (Poland) via Android Authority