sourcing cheap components for conversion

[bennelson]

You don't need anything too powerful for for the brake vacuum.

I just used an old little industrial pump that happened to be DC. I got it from a friend who always has weird junk like that laying around.

A fair number of odd little parts can be gotten from forklifts and other industrial equipment in junkyards.

[billhac]

you can build a pack charger your self, for under $150 us, it does not take much electronics know how to build. and the component should be available where you are.

[Simy]

I was just going to suggest going that route with the charger. If you can't make it yourself have the same person who is making your controller make it for you =)