A question for the pickup gurus that hang out here.

Anybody have an idea where I can get a 5-string pickup for a solid body mandolin I'm building? Can I use a regular guitar pickup and just let the extra pole hang-out with no string on it?
How 'bout using a 5-string bass pickup slanted to match the skinny string spacing of the mando?

Any advice on this would be much appreciated.

Thanks,
Leonard B. Akers