I opened up my Orion last night to check how much space there would be and I don't see how it could fit. Besides the fact I have an l.e.d. switch in there I don't see how it could fit as it's very tight.

At the northern California get together I had Ron look at the cavity on my Epic to determine feasibility.  It looked doable, but might require a little cutting.
 
The knobs would almost definitely need to be re-arranged, with the filter going where the pan is, the pan going in the volume spot, and a new hole for the volume.
 
The filter module would get daisy chained in between the pan and the bass/treble controls.
 
Bradley

Hmmm, sounds like more of an operation than I'm willing to perform on my Orion. I guess there's much to say for a bass/treble > filter/q swap with the possibility of swapping it back to original specs.
 
Wilfred

Build a little box for the treble & bass control, jack in/jack out and put on top of your amp  
(probably won't work unless you find a way to provide power to the units...?)

not entirely a bad idea Flip!

I'd definitely recommend a drill press. These things need to be perfectly level.  You wouldn't want whoever get the alembic after you to go, oh nice...they added this later. Or have Mike do it.