And it's pretty much spot on perfect! It's this guy here, the On Stage RS7000.
[VIDEO]http://www.amazon.com/gp/product/B0002GY7MO/ref=oh_o00_s00_i00_details]Amazon.com: On Stage RS7000 Stage Monitor or Guitar Amp Stand: Musical Instruments[/VIDEO]
The Mesa fits in there perfectly, with plenty of support and absolutely no wobbles. It's about 4" higher than the top edge of the HD1221, which is exactly where I hoped it would end up.
I'm in the seventh level of cable-cleaning hell right now so pardon the wires, I'm still waiting on my power amp (which Carvin hasn't shipped yet... ). Once it shows up I'm going to go through and tidy it all.
Not bad at all.
Is that a Sherman, btw?