You can discount the lesser numbers of the Express/Savannah, as they have to share the same line with the new Colorado/Canyon pickups. GM is running that plant full out 7 days a week and can't keep up with either the vans or the pickups. The vans have been given secondary production priority, so there's a shortage of them big time. This was part of the reason they discontinued the 1500 version of the van for 2015 to free up production numbers.
Ford has been running the Kansas City Transit plant 2 shifts, 50 hours per week, with a couple Saturdays per month thrown in to keep up and build inventory.
According to guys over on the Transit forum, the ordering time to receipt has lessened considerably since springtime. The biggest holdups are still the medium and high roofs because of their non-standard shipping requirements.
Currently no need for Ford to finally release the RV package version of the Transit unfortunately...
Bob & Sharon
2019 Winnebago Travato K (2018 Chassis)
Past RV's: 2013 WGO ERA 70A, Chevy PW Lexor
Itasca Navion, 29' Jayco 5th Wheel