It will be the 3rd phone to get ICS. Seeing how the Nexus S is still getting stable and the MI One is not even close. I'd say were 2 weeks away from a small beta (that might not be publicly released).
Think of it this way. Currently the Nexus S is fighting both ICS kernel bugs and MIUI v4 bugs. Xiaomi wants to eliminate as many MIUI bugs as possible before porting to other devices. Otherwise they will be playing bug fix for lots of devices at once. They want a semi stable product before they begin branching it out.