Yeah, multipliers are a really interesting idea. I remember reading of a gun from amazing1.com that could do similar things to a tesla coil using a multiplier instead. Way over priced and you can get the plans free anyway. Found it here
I think they might have an article on coil guns too.
Why are you gonna need a multiplier anyway? The charging circuits in the cameras will go to the right voltage of the caps anyway. Or are you gonna wire the caps in series for a higher voltage with a smaller capacitance for a quicker recharge time?