Nice! I drool at all of these WeldTec van threads. Makes me second guess wether I want to save up for a 4x4 conversion or do one of these sweet lifts.
I do have some info to contribute that may be helpful. I did a lift on the cheap and found these resources for parts.
Lift:
Front coil spring spacer for 1.25"-3" of lift can be sourced from these guys. They are the same as found on 1988-98 Chevy 1500/2500 2WD, 1999-2006 Chevy 1500/2500/3500 2WD trucks. A full list of applications is available on the site. They are the 1900 series lift spacers, and they work on Savana/Express models 1500/2500/3500 (1996-present). Talked to the owner Steve, who was helpful, and was able to figure out that these would work on our vans. Sent them out fast, I did the install, and he updated his site. Obviously not as trick as WeldTec, or swapping in springs from a Duramax equipped Express, but a good way to start out.
http://www.mcbayperformance.com/ProductDetails.asp?ProductCode=1900T_SERIES
If you are doing a rear lift with just spacers, JEGS Performance was the best place to find what I was looking for. I only wanted to do a 1" lift in the rear. I utilized their universal lift/drop block, (which I did have to modify by drilling the guide pin hole to 11/16") and utilized a universal set of square u-bolts from Superlift Suspensions that measured 2.5"x10"x5/8" (Stock measurements for a 3500 Express is 2.5"x9"x5/8"). You could probably run a rear lift of 1-2" blocks with this assembly. Ran about $67 shipped for blocks and u-bolts, which was cheaper than I found for any kit. They have an assortment of sizes available.
http://www.jegs.com/i/JEGS-Performance-Products/555/60810/10002/-1
http://www.jegs.com/i/Superlift-Suspension-Systems/426/11004/10002/-1
Bumpers:
This is a big one. I sent out an email, and received a fast reply from these guys; You can order a MOVE DIY bumper to weld up yourself. They are awesome bumpers that you can customize to however your budget or style wants to. They now have it listed on their website. (I was in contact with a guy named Chris, and he was very helpful.) These bumpers are steel, but they are an alternative to Aluminess bumpers. They currently have a front and rear bumper option listed for a 2003-2016 GMC Savana 3500, which means it will fit 1500/2500/3500 (2003-present) Savana/Express vans. I will be ordering one within the next few months.
https://www.movebumpers.com/
Hope this info helps somebody out. I had to look around for a while to find very little information on the 2WD Express vans, but lots of good info on the AWD. Happy trails!