As a former owner of a small Toyota pickup, I see several benefits to having a power outlet in the bed of the truck. If you're off-roading, camping, or performing a variety of other tasks where it might be dark, that outlet is a great place to plug in a shop light. There have been a few times I was off-road and a 115-volt outlet would have made a task at hand much, much easier. No, it's not going to run an air compressor or welder, but that doesn't make it useless.
I disagree with Rusty that these mid-size pickups are any cheaper to purchase or maintain than a full-size truck would be. As Eric points out, bigger trucks tend to include a lot more content for very little extra money. Historically, full-size trucks have offered better incentives and returned nearly the same fuel economy as mid-size trucks like the Dodge Dakota or current Toyota Tacoma and Nissan Frontier. The only true small truck on the market is the Ford Ranger, but it has been neglected to the point of being irrelevant.
I wish Toyota would return to its small-truck roots and offer something the size of the 1985 Toyota pickup I owned. That truck struck the right balance between size, fuel economy, and capability. I would love to purchase a new pickup with a regular or extended cab (NOT a four-door behemoth crew cab) and a reasonably sized bed that would accommodate a load of 2x4s, a dead deer, or other traditional truck cargo. This truck should be able to get out of its own way with a four-cylinder engine and offer a six-speed manual transmission with four-wheel drive. I need just enough off-road capability to get down muddy two-tracks to find a great hunting or fishing spot, but not oversized tires that add weight and hurt fuel economy. Until then, it looks like I need to shop for a late-1980s Toyota pickup from a part of the country without rust problems and perform a few upgrades of my own to fit the rest of my needs. So much for progress...
Phil Floraday, Senior Online Editor