I legit tried to get one of those new. They're practically indestructible and have shit tons of storage. They would be awesome get arounds on the farm. If they were AWD or 4wd, I would give my left leg for it.

Sadly, you cannot, from what I can tell.

Those old postal vehicles were made from the GM parts bin with a custom shell built to spec, though most of them were from the S-10 platform. They are not indestructible, the USPS started scrambling to buy COTS vehicles while the NGDV was in development.

The S-10 itself is a really good farm truck though, so I'd keep your eyes on the market for one. Or maybe the equivalent Ford one.

I'd buy one. USPS could get into the large storage and moving business.