My grand vision (doesn't everyone have a Grand Vision?) is to have a collection of applications which all use this abstraction layer. So I'm waffling between a "suite" config file or a separate abstraction-layer config (file, or at make time).

I agree that randomly probing for potential back-ends is less than polite :-) (and no-one has implemented Mind::Read, yet), AND presumably whoever is installing will know what they want to use....

I hadn't thought of the "automating the install" issue with an interactive make.

Gak. /me mentally runs in circles.