I flashed another 2.1 sense rom for now, but I'm looking forward to try this one again.
I patched the partitions first, installed the X package, then X.1 and that's it. Wouldn't boot.
I think I'm using RA 1.6.2, SPL is the 1.33.2007 version (the one flashed by RadioSwitcher).
I was actually looking for a Froyo + Sense release, but now that I found out you can use Apps2SD in Éclair, 2.1 is ok for me.
The problem is that you are using the wrong SPL. You need a 6.35 radio and a 1.76 SPL. Just change that and you have your problem solved.
Note: 6.35 Radio ALWAYS requires 1.76 SPL. 3.22 Radio ALWAYS requires 1.33 SPL. If you mix them the phone won't boot.