Why not research what a HID ballast requires? they are simple to make, but i highly doubt you can make one without order some supplies off the internet.... ...
Yes, you can make your own. They both require a transformer and a capcitor, then one just needs an ignitor and I forget... I think there is a secton in FAQ about making your own.
its not being cheap, they are not that hard to assemble, and if you have the know how and time, why not save a few bucks? use that somewhere like ventilation or nutes?