I hadn't seen that setup before either until I started digging around for a turbo kit for my Silverado. It appears that it's the standard layout for most of the newer chevy truck single turbo kits out there. KB Racing and Trick Performance, the two largest producers of silverado turbo kits, both utilize that setup. You can actually purchase that manifold separately from Trick performance if you're building your own kit (for a mere $600!).
Check out these sites, they show more on these kits:
http://www.shop.trickperformanceprod...1.htm?page=all
http://www.kbracing.net/about.html
I've thought about using one of these kits on my C10. The only real downside I see is that you have to use the stock truck manifold on the drivers side which doesn't fit real well.