There are other companies that do conversions. Take a look at this link.
http://www.thundersgarage.com/4x4vc.html. I'm very satisfied with my Quigley conversion. Others may be slightly more capable but there is always trade offs. Quigley is very time tested and well engineered. (And the only Ford authorized conversion.)
I have an 07 EB. IMHO the old style front ends look better. I'd buy a regular length van if I bought one today. They have a lot less rear overhang and look better. They have been making the old style front ends since 1992, so the parts are cheaper to replace. That will effect your insurance rates. Not to mention things like aftermarket bumpers, front hitches are more money than the old style front end.
The engine/transmission combo is more important than the other items 07 vs. 08 present. V10 or diesel, you want the 5R110 tranny. It does not come with the V8.
The newer the van, the more unnecessary things like traction control, tire pressure sensors, etc, may be added. Starting in 08 the 2wd front end has been updated, but all that is replaced when the conversion is done. I think the 08 has bigger rear brakes than the 07. 09 brings a new dashboard.
You can always black out windows where cabinets are installed.