Gamo PT-85. About the size of a P226. DA/SA trigger mechanism with reciprocating slide. Pellets only, eight in a disk on each end of a "magazine stick" inserted in the grip bottom (and flipped when each end runs out.)
Gamo PT-80. A little smaller, about the size of a Beretta PX4 Compact. Same mechanism, minus the reciprocating slide action.
Gamo PT-25. About the size of a PP or PPK. Probably good for self-defense practice if normally carrying a similar firearm. I've never shot this one yet.
I think there is actually a P226 model, probably made by Umarex, I saw online recently.
Truth is, there are scads of CO2-powered replicas of modern and older guns out there now. The SiG "We The People" 1911, with its aged-appearance, looks very nice. It runs about $100. The others above all run a lot less. For what you're asking it to do, I don't think you could spend $400 unless you're buying three or four guns (or more) if you wanted to. CO2-powered auto-pistol replicas just don't get up there in price.