By depth I mean from the front of the drawer to the back of the cabinet.

My question is what would be the minimum reasonable depth for a drawer?

I am designing a cabinet to fill a space, but the depth needs to be minimal
due to it sticking into the room where a hallway enters.

Could I get by with say 12" deep drawers. Would I be able to find
full-extension drawer slides that could be easily adapted to work with the
shallow depth?

Thanks for advice. Oops, sorry, advise. g

-Doug