Secret storage compartments on wagons?

[Zarius]

I'm looking for pricing, other than the 3.5 Complete scoundrel, on hidden compartments on vehicles. Specifically wagons, since the Complete scoundrel only mentions boats and ships. Anyone got any ideas? Or suggested pricing?

[Claxon]

Compartments in the axles or hubs of the wheels.

Probably a false wall in the wagon behind the driver's bench.

None of these are likely to be very big, but they are likely to be hard to detect.

[Zarius]

*blinks slowly* That is disconcertingly awesome, assuming the item doesn't need to be kept stable. Or use something to wedge it.

[Kayerloth]

Now combine the very mundane small hidden compartment that has a larger size Bag of Holding or an item under the effect of Shrink Item within or something similar. Add Nondetection to counter Detect spells.