I guess I'm with a lot of the longer time membership here. I absolutely think they should, and don't really expect them to.
Unlike most of the other players, GM can pretty much throw together a parts bin car and get a pretty impressive PHEV with minimal new engineering effort or new parts. Unlike the poster mentioned in the article, I wouldn't start from the CT6 PHEV, though.
I'd take a page from Volvo's book, and start with the guts of a Bolt and a Malibu Hybrid (or a Volt but with the Malibu's bigger engine.) Since GM has been using independent front suspension forever, it isn't really any loss of capacity to drop the Malibu transverse package into the front - and by doing that it creates a lot of space between the frame rails to tuck the Bolt battery pack into. The Bolt's 200 HP drive axle will require some changes to support the rear of the truck, which I believe is still solid axle and certainly rated for heavier loads than the Bolt, but it's shouldn't need a lot of modification.
That gives about 350 electric horsepower (assuming the pack can take it, but GM's past packs have had much higher C rates than this,) and around 400 horsepower with the engine on. Even with a big heavy truck, it probably gives close to 100 miles of EPA electric range, and makes the truck far more efficient on gas by better matching the engine size to the load. The only place it might come up short is mountain grades while towing in extended range (122 engine horsepower...) - but the pack is certainly big enough that a version of Mountain Mode or GPS route based management of the battery reserve should see it through without slowing.
One obvious benefit (as pointed out by Via) is that you can easily add a battery driven inverter as a factory option (or standard?) and run power tools or a house from it - 15 or 20 kW will cover most anything people are likely to want, and won't make the truck sweat at all - and between the inherent efficiencies of the powertrain and being able to cycle the engine only when needed, it'll be by far the most efficient generator you can buy.
You can buy both complete cars for about $65k without any rebates, so unless the Silverado sheet metal and interior fittings are somehow much more expensive (and, mind you, the two cars combined have far more weight (~7k vs ~5k) and volume of such things,) GM should be able to make a profit selling it in the $55-60k range before any rebates - pricey, but not that far out of line with what folks are paying for some of those trucks already.
