I doubt XDA developer ever slept in night as XDA senior member tgascoigne has ported an initial release of Android 4.1 Jelly Bean to HTC One X just one day after the official release of Android 4.1 on 27 June 2012. It is not like Galaxy Nexus which receive an official version of Android 4.1, customized version of Android 4.1 ported on HTC One X is still under development where some known issues has been clarified.
According to XDA, this alpha release is based off of the GSM Galaxy Nexus Jelly Bean image, where so far the known issues include:
– Probably More
But never get disappointed since XDA developers never sleep at night (wait to clarify), I believe a working ROM will be released in short while before the official update released by HTC.