I need to route the control cavity either way, so routing for the Cirrus-pre PCB would be a piece of cake. So that's a non-issue.
(plus I already have it, and would rather not buy another pre to replace it. this is a budgeted project.

)
Shielding isn't a problem. Conductive paint for-the-win!
EMG J's is a possibility, I'll have to look into them.
*wanders off to the Jazz p'up shootout thread*