I just can't wait, and found this update package in A500 Development forum.
It is official ICS update, at least it is from Acer update server. But after update, the version become WW instead of COM
The file name is Acer_A500_7.014.14_041.203.01_COM_GEN1_1333444737199_8ec8b991.zip.
So, in my opinion, it is for Acer_A500_7.014.14_COM_GEN1.
After using this update package, the A500 system is rootable using blackthund3r's one-click root tool.
The 6.0 version of this rooting tool also brings Acer Ring!!!
Big thanks to blackthund3r!!!