I'm not entirely disagreeing with you. I'm only saying that teams don't work for free. They need money or miles, and FedEx doesn't offer money. If they took a 400mi meet and turn and canned it for an 800mi linehaul, at $1.45/mi it's not enough to cover the expenses of owning a tractor built in the last decade. Will they allow older equipment? Maybe, but everyone I've ever talked to is expecting no more than 7-9 years old on average. This includes FXG and FXCC. I won't speculate much more than the rate, since it could surprise me and be more than that, but I suspect not considering most US carriers are barely paying $1.00/mi plus fuel surcharge to contractors, who have to make it up on the mileage side, fuel economy and so on. And hope the truck doesn't break.
I would be incredibly surprised if this "trial" grows beyond a handful of contractors purely because most owner/operators running team look for long length hauls. Short ones won't pay enough. If FedEx tries 800mi/day, they'll get gypsies in 15 year old beaters from Schneider. And FedEx is a very image-conscious company, if nothing else, so I don't think they want that either.
I could be wrong, I'm the first to admit that I'm not always right. But as a rule, I look at something and ask myself if it makes sense. To get teams to run such short hauls, they'd have to pay pretty close to what a pair of company drivers are already paid to cover that distance. To save money, they have to pay less. To pay less and still get any interest, they need to offer miles.
As a team operator, my tractor covers 5900-6200mi a week. This is what it takes to pay for the truck, fuel, maintenance, taxes and supporting two homes that we still find time to get back to every week. I departed FedEx because they decided to charge for plates and insurance after years of not doing so, and the rate was not raised to compensate nor was I given more miles. Maybe you don't care, but this is how contractors operate.