Maybe not the cheapest...but great people to deal with: http://www.import-autoperformance.com good quality stuff and generally a bit of a NICO discount, give Marc a holler and I'm sure he could help you out...but it'd be a modification of their normal KA24e kit since it's a truck. Heck, any off the shelf kit would have to be modified a bit.
RealNissan's KA24E manifold is a modified cast iron manifold with a welded on steel T3 flange. Any cracking issues there? Ask about a warranty on the manifold.