Umm, im a n00b so ill try to answer your question, im sure someone else might answer it better tho..
1. First off, you need to purchase some chemical that will remove the paint... I used an all purpose stripper for stains, varnishes and paint. I got it for like 20 or 30 bucks at walmart. Once you poor this gooey liquid on the guitar, let it sit for a while , i waited about 2 hours. fter that time, if you feel the stripper sat long enuf, get a scraper and begin scraping the paint off. Since you said black, im guessing that this is a plain painted body,. Good, because thats what im trying to explain. I never worked with stains so im not gonna promise anything if you actually mean a transparent black... anyways, after you scrap off the paint, it should come off like a pastey jello.. it should be really simple to take off.. if it isnt, let the chemicals sit longer. after you feel the basic color is off youve completed the first step...
2. now you need to get some wood wash. Its basically a chemical that cleans off the chemicals in the prior step.. This will help prevent paint dissolving later on.. Once you poor it on the wood and is wiped down good, you can sand the body and get started on the new paint coolor. Since youre looking into buying a complete new Veneer, youll need to measure the body to see hom much you plan to saw off the top. since your trying to accomplish so much, you might just be better off buying a Soloist body from Warmoth.. especially since you plan on decking out some money on a 5A quilt top.
Good Luck..
~korge
EDIT- o yea, for those stains like those sunburst, youll need to get an airbrush to spray an Alchohol based stain around the edge. this may cost some money for a good airbrush... but if you want a basic stain, just get some normal water based for the center color, then get the airbrush and spray the second color around the edge.. just my .02 but someone will definitly explain this better..