HTC has done what it usually does when a new phone is released: it provides access to its kernel source, allowing developers to create custom ROMs with working radio, WiFi, camera, etc. Since the One X has two models, international Tegra 3 and North American Snapdragon S4 versions, they’re required to provide both.
Because the Tegra 3 relies on a significantly older Android kernel, based on 2.6.39, it will never be compatible with the Snapdragon S4, which uses a more up-to-date 3.0.8 kernel. As a result the Rogers and AT&T versions are missing, but should be provided in good time.
Recently, HTC came under fire for disallowing the bootloader unlock of the AT&T version of the One X, implying in a statement that it was a carrier policy more than anything. The Rogers model has no such encumbrances, and is being used as the basis for a developer community.
If you’re interested in seeing what HTC has to offer, however, head on over to its developer page.