Ok I think I've reached a point where I feel comfortable enough to try this. So I don't have remove the bin.img before flashing the ROM through clockwork. Then just go fastboot, CD (change directory for anyone who googles this) to where the bin is...
Am I reading correctly, a HTC unlock can flash kernels via fastboot? This is mainly what is missing from there unlock method, besides splash images, correct?
My replacement phone should be here tomorrow, I am worried about getting 1.50 hboot. ...
This customized version of TWRP will flash and run just fine:
All I did was extract the recovery image and replace the kernel with the stock recovery kernel. Everything appears to function just fine....
A little more strangeness to add. You can flash / overwrite the boot partition while booted into android.
I have hboot 1.5, and am running cm7, it works wonderfully. There is very little extra work if you use fastboot to boot the recovery.