printable circuit board?

I'm curious as to how thin a printable circuit board with all the components, such as resistors and capacitors, can be. It seems like extra thin pcbs can be as thin as 0.15mm. Do resistors and capacitors get that thin as well?

I pretty much don't know anything about electric circuits, so please bare with me.

I'm basically trying to build a USB charger for a 3.7v lithium battery. I'm aware that USB delivers a 5v current so there needs to be some sort of current regulator. My question is, based on the amount of current that is traveling through the circuit (several 100 mA?), approximately how thin can the pcb get with everything attached to it? I'm guessing that there are capacitors and regulators that are less than 1mm, but I'm assuming that the capacity of those capacitors would be too small for my particular needs.

Besides the current regulator, I'm thinking that some sort of switch would also be needed within the circuit to prevent the battery from being overcharged. How would this affect the overall thickness of the board?

Any input or advice will be greatly appreciated.

Thanks