The RTAI I used is based on Shabby & Memleak's master, from here: https://github.com/ShabbyX/RTAI
Here's my branch, this is what produced the 3.4.53-*-rtai kernels I published: https://github.com/SebKuzminsky/rtai/tree/prerelease-5
In my rtai prerelease-5 branch there's a file called Notes, which describes (tersely) how i prepared and built everything.
Here's the kernel sources: https://github.com/SebKuzminsky/linux-stable/tree/linux-3.4-rtai-2
The kernel source is mostly just vanilla upstream from kernel.org, with the rtai patch applied. It also has the .config i used, it's called linuxcnc-rtai-config.