<  That brings me to another question, can the ST506 controller speak
<RLL? I have a 122MB RLL drive laying around, I doubt it does, just thought

I think not but, the rll drive will run MFM.  It will be about (80mb).

<I'd ask. RLL drives use ST506 and MFM use ST412, or am I backwards?

Ah, ST506 is a Shugart 5mb drive(6mb unformatted), ST412 is a Shugart 10mb
(guess what 12mb unformatted) drive that also has the same interface as a 
ST506.  So based on that the answer is: _yes_!  Oh, and RLL drive are 
basically MFM drives with tweeked RW electronics. In some cases they are 
the same drive.

Allison