Ok time to chime in on why i've not pushed an update:
1. The Mi-one is largely still a China only product with some now just only starting to get imports.
2. The ROM was largely stable from 1.12.30 onwards, 1.12.30 was I believe 2.3.5g so stable are just good dev builds they deem stable.
3. ICS ROM was out in a few forms, 1st MIUI V4 then it was pulled due to major stability issues.
4. A Stock ICS ROM was then created for the Mi-one, this was also an internal beta to test general hardware performance of the device before an implant of MIUI V4 would be tested by users in the beta group.
5. Last week a private beta was released to testers (i.e. I cannot give it out publicly) However the size of the download is 300+MB this is because: a) It includes a utility called MiFlash which allows a user to flash the ROM via PC. b) It is required to get MIUI 4 ICS onto the Mi-one. In 2.3.5K there was new partition sizes added. Within recovery the partition (system) has to be updated in size to allow for MIUI V4 ICS. c) Flashing the 2.3.5K update generally went fine, however flashing the 2.1.18 update was sometimes problematic.
In closing I am currently beta testing 2.1.20 and there is still some stability issues and layout bugs, nothing that stops day to day use too much except for the very annoying random reboots, usually when writing text messages and a lot of apps FC like Root Explorer and occasionally Yaaic.
Once there is something we have permission to release we will do so. For now the process is very convoluted and not easy for most users i.e flashing from a PC system and modem images which the latter is very dangerous if you mess up! As I say more news soon.
I have Mi-one V4 + instructions, just need to look at what needs to be changed versus the Nexus S version, once i've got that done i'll post it + instructions on how to flash via Fastboot. Fastboot is the only current means in which to flash the new v4.0 update the mi-one.