cool project, i think that you are going to have a very enviable truck when you get done with it. i like that you are going to keep the 6. if you are gonna lift it i would suggest superlift soft ride springs, they are awesome. i would also suggest this site:
www.offroaddesign.com they make some great suspension parts, check out their rear shackle flip kit. works great on my buddies big chevy, easy lift for the rear. i really like your truck and i think that you are on the right track. good luck.