This parallels the current trend of crossovers, where a car-based vehicle can offer some of the towing and payload capacity of a body-on-frame SUV, with some off-road ability too. And you can't argue that no unibody vehicles have capability: The LR4 is one of the best off-roaders out there. And neither the Touareg nor the Grand Cherokee gets left behind on the trail, either. But when it comes to pickups, no matter the platform, they would have to get the look right.
Another really interesting phenomenon could happen if compact unibody trucks were to appear. Compact truck buyers could have the choice of hard work or play. Something like the Pontiac ST concept had the potential to be a street rod with a useable pickup bed. Any modifications that could be done to GM's 6.0-liter V-8 would've worked there. I still would love to see that concept reborn as an El Camino, but I'm not holding my breath. Add the handling of a car, and it would be hard to beat that level of street performance.
I don't think it would make sense for the entire segment to switch to unibody platforms. There is still a need for true work trucks in this size category. Having said that, there are some companies that have a unique opportunity to offer both. The way I see it, one company that has a more realistic shot of accommodating both body-on-frame and unibody compact pickup buyers is Jeep. Jeep could -- should -- build a truck on the Wrangler Unlimited platform. That would give people who love the fantastic old-school, solid-axle, off-road capability of the Wrangler a truck bed too. The Unlimited's 116.0-inch wheelbase is certainly long enough to fit in with those of current compact trucks and is three inches longer than that of the 1992 Comanche, the last Jeep pickup.
Another interesting option would be to use the platform that lives under the new Grand Cherokee. In terms of size, it also fits right in: The 2011 Grand Cherokee's wheelbase is 114.8 inches, plus there's a lot of off-road ability there. It can tow 5000 pounds with the new 3.6-liter V-6 and up to 7400 pounds with the Hemi. With all the option boxes checked, something like that would be too expensive, but a decontented V-6 version would be interesting. I'd love to see something like that happen, but Jeep has said it has no plans for a unibody truck. We may still have a chance at a Wrangler-based pickup, though.
Would you be interested in a compact unibody pickup, if it had enough capability to meet your truck needs? There's a lot of versatility in unibody platforms, but is it worth losing some capability?