Crash test scores are a concern, but it you're shopping for a truly compact pickup truck, the 2012 GMC Canyon is probably a better pick than the Ranger or Dakota
To say that diesel is becoming mainstream in America is still a stretch; the reality is that more and more companies are coming forward with sophisticated diesel powerplants that will eventually end up in some cool vehicles. New diesels will help manufacturers meet more stringent CAFÉ (Corporate Average Fuel Economy) standards that the government is demanding.
The 2012 Chevrolet Colorado soldiers on as the only truly compact truck on the market (with its Canyon twin), but are you sure you don't really want a mid-size truck instead?