Stealth pickup suggestions

This idea may prove to be nonsense, but...

I'm in the middle of building a mutant out of Warmoth parts. I had the body carved out for 2 P90s and a strat single coil in the middle position, with the idea of dropping in a hidden middle pickup beneath the pick guard. I have a set of Fralin noiseless P90s, and I think they put out around 9k. Any suggestions as to an appropriate strat pickup to complement these and add a bit of quack?

I suspect it will need to be a bit hotter, as being underneath the pick guard it will be a bit farther from the strings. I really don't want some crazed high gain pickup, though, as I am really only after variations on clean sounds.

Any ideas?