CyanogenMod 11 now available for Android One devices
A custom recovery / unlocked bootloader is all one needs to install a custom ROM. Varun.chitre15 has gotten to work on a CM ROM for the Android One devices and it can be flashed to any one of the three. It is still in alpha and there is still trouble with data connectivity, Wi-Fi, and the second SIM card not being detected.
Google's Android One program aims to bring entry-level devices with adequate specs to developing markets. It would be interesting to see, now that it's been made possible, what modders will be able to do with the affordable hardware.
source: XDA Developers