The Econoline is not gone quite yet. Sounds like a few more years. By that point, something new might be better. This is from Automotive News:
Econoline, Transit: Mulally's global vehicle plan hit its first snag in February when Ford delayed its full-sized commercial-van program. That vehicle, the next generation of Ford's Transit van, will be sold around the world. U.S. sales had been slated for the 2012 model year, eventually replacing the Econoline van.
The plan is intact, but the timing has slipped. Now the North American version of the Transit, code-named V363, is expected to go into production for the 2014 model year at Ford's assembly plant in Avon Lake, Ohio. The Econoline could carry on for a short time after the Transit begins, but eventually it would be discontinued.
The whole article was here: http://reviews.cnet.com/8301-13746_7-10296358-48.html
So, it sounds like 2014 or even a little further.
Also, by that point, there might be better options out there than the old E-Series. I know it sounds like heresy, but that's life.
All the Tacoma guys freaked out with the big re-design in 05, but most people like it now.
Also, the thing to remember is that there will be a definite need for a commercial-grade van/truck that size. THAT will not change. It's not like plumbers and other contractors will suddenly need a smaller, less heavy duty vehicle. Ford knows this, too.
That rig you posted is pretty interesting, too.