If you need CJ parts, you really can do yourself a favor and get ahold of DMCJeep on this site. Denny has every single part you'll ever need. He isn't dirt cheap to deal with, but he's on the low side of average as far as his pricing. If nothing else, send him a list of what you need and if he doesn't have it, he might be able to help you find it.
Enough of the shameless plug... just start doing what Renegade is saying. Look here, and on any of the other jeep sites, and on craigslist (get craigslisthelper for your phone if you have an Android/ iphone) for parts. Build a stockpile. Use what you need, sell the rest. Even if you buy an entire D30 for the disc swap, you can still sell the housing for $20. When I did my CJ, I went out to Lansing to pickup a free D44 rear housing and ended up buying a D30 front with disc brakes, a brake booster, master cylinder, and a spare set of cro-mo axle shafts for $150. Most people on this site aren't JUST selling one piece of a Jeep, and all it takes is flashing a bit of money to get most of us from "thinking of selling" to "sold".
Good luck with your build either way!