Originally Posted by E350
@JWA has done such a swap, although I don't know if it was 2008 or newer.
Actually what I did was replace an '03 E250 instrument cluster (without tach) for a '99 F-Series cluster w/tach. Its a cool feature, I had plenty of time to devote to the preliminary work and at this point I'd say it was relatively "easy". Of course that's highly dependent on your skill level and general familiarity with Ford's wiring schemes and practices.
I've not tinkered with swapping the entire dash board but knowing Ford there would be a few wiring issues to overcome. Physically it should be almost a direct drop in as the bodies are probably very much the same from 2007 to 2009.
I'm not sure the aesthetic change would be worth the effort but that's just me. Its possible air flow through the defrost and/or dash vents was improved but for the most part I'm okay with the pre-2009 E-Series I have presently.