Well I am looking for a backup gun right now...
What's your primary piece?
Well, for a backup, derringers like the Bond aren't all that compact, and they're heavy (compared to alternatives). Don't get me wrong, they're very well-built pieces (maybe the current best of the breed), but many folks prefer something lighter for a BUG.
As others have pointed out, j-frame-size revolvers are around the same size as the COP, are lighter, have better triggers, and 24% more capacity than the COP (and they're in production). Of these reolvers, the Ruger LCR is the lightest (at 13 oz) without going to the expensive scandium alloys.
A Kahr PM45 would be smaller than your primary and maintain ammo compatability. Fairly close to the size of a j-frame actually, although a couple of ounces heavier.
Going smaller still for a backup piece: you have the Kahr PM9 and the small 380acp pocket pistols (P3AT, LCP, etc.). The NAA Black Widow in 22 mag with the 2" bbl can play this part as well, but it's a smaller cartridge than many folks are comfortable with (a real last ditch, shoot and scoot sort of gun).
Anyway, those are a few suggestions. Have fun looking.