I, my wife and our baby will arrive in SFO airport, and will stay in the South Bay. We will have 6 pieces of approximately 24" (61 cm) luggage, and allowance for only one taxi. Will we be able to transport ourselves and the luggage in a regular cab, or should we arrange something special?
You likely won't be able to fit into a "normal" cab, however SFO normally has a good assortment of types of cabs available, ranging from those with just larger trunks up to minivans and the like. There are generally taxi marshaling staff at the airport who will be able to assign you to a taxi that will work for you.
Keep in mind that a cab to the South Bay likely won't be cheap - depending on exactly where you are going it's a 30-50+ mile trip, and due to the taxi regulations they will charge you (at least) 1.5 times the fare to cover the return portion back to the airport as they are not allowed pick-up passengers for a return trip.
Since I finally made this trip, I will write what happened here. Mostly it is as what Doc said, when we arrived in SFO, we proceeded to the "Taxi" area as shown by the signs. There is an officer there, and when we showed him our luggage, he said that those won't fit in a normal cab. He then told us to wait while he called a bigger cab. In less than 5 minutes, a cab appears which is about the size of a Toyota Sienna. It has cargo space at the back that is more than enough for our luggage (I guess it can take 1.5 to 2 times that easily).
As expected for a trip to South Bay, they charged 1.5x the metered fare.