As far as a thread on painting 1/55`s goes I dont think any of us has done one. But general consensous is you can do it one of two ways. With rattle cans, carpaint or Krylon seem to be best. They are great for durability of your gonna play with em and do transformations. If you want something for the display case them you can paint em up like models. It really depends on what you want to do and your experience in painting things.
The only real thing to remember is making sure the surfaces are keyed, clean and grease free or your paint wont stay stuck for long.