Over on XDA Developers, a user named “Football” has posted a test only build of Jelly Bean for the HTC One X, identified as 3.00.999.7 with a large 641MB download size. Users on XDA are being urged not to install it due to the unstable nature of the test build. Football said:
And last but not least, this is highly unstable release, 999 ID means it's only for test purposes and you shouldn't use it for everyday usage.
Instead of trying to flash this unstable ROM it's probably best that everyone takes away the thought that HTC are working on Jelly Bean for their flagship device. With a near-working build such as this, it can't be too far away!
For those of you keen to try this build regardless of the forewarned instability, here is the download link.
If you do try this ROM out, please let us know your experience with a comment below.