The arm of the hinge (small, plastic insert with the company name)
The bottom of the drawer (need to take it out)
The back edge of an adjustable shelf (need to take it out, sometimes you will see a sticker)
Branded into the interior side of a drawer
Top edge of an upper door, bottom edge of a lower door
Other than that, you could remove a door and take it on a shopping excursion to HD and Lowes :). My guess is if the home is fairly new and a tract home, a custom cabinet shop did not make the cabinets. Usually tract builders use national suppliers for their cabinetry.
Unless they are out of production, you should be able to find them somewhere. It's a matter of using the tools available to you.
Barbosa Cabinets in Tracy does alot of the cabinets for home builders in Mountain House and Lathrop. If you own a newer home then you might try giving them a call and asking them if they produced the cabinets for your subdivision. If they did, you should have an easier time getting a match. If they didnt maybe you can find an original home owner that knows who manufactured the cabinets.