It sounds like you're in a part of the USA where there just aren't many of these yet...but they still exist. Just like the phenomenon I'm told by a specific manufacturer that there are very very very few ~2018 Transit 130WB MR cargo's in the NE USA/SE Canada, yet there are many here on the west coast...doesn't mean the west coast ones don't exist.
I'm not sure where you misread that both Transit gas engines are too small/complicated...3.5L Ecoboost's 400ft-lbs of torque isn't "small" IMHO. Yes, these engines are direct injected whereas the E-Series weren't, but if you practice meticulous preventative maintenance (full synthetic oil changes every 5k, blow carbon out with the "go" pedal, etc), any DI issues will be minimized. In regards to a 4th gen E-Series by comparison, you're talking about a van that was engineered back in 1992 (28 years ago!). How much safety/technology has drastically improved in ~3 decades? A ton. Yes, technology isn't perfect, but drive a newer Transit(even RWD) back to back with even a very solid E-Series; it's apples and pears for sure...especially if you're talking about an antiquated leaf-sprung E 4x4 conversion.
4th gen Econoline aesthetics were the same thru 2007. In 2008 they updated to the new headlights/grille(note; there were both the "basic" headlights with amber turn signals above the "rectangular sealed beam headlights" or the "aero" headlights which were one complete acrylic(?) headlight assy w/ turn signal bulb inside), but the 2008 interior was the same as 2007(curved dash lines around stereo area, half moon HVAC vents). In 2009 they updated the interior(now rectangular dash lines around stereo area, full round HVAC vents) so now both the front end and interior were updated to coincide with the new F-SuperDuty interior style. Interesting to hear you prefer the front end looks of the Transit vs the 2008+ E-Series. Took me awhile to accept the Transit's "guppiness" but especially with the right mods they look cool IMHO. I've eventually come around to understand how far superior a van the Transit is compared to the outdated E-Series in soooo many ways. My $0.03.