Hi Noelio
Thanks for the info, and definitely for speaking up! I am familiar with what a VESA Feature Connector is, and unfortunately everything I found suggested it is not that - but it could be related. VESA feature connectors are normally a 26 pin header, but the Dolch video cards in single-ribbon form only have a 20 pin header.
DFP however is a bit of a different story. I don't know anything about it, your post is the first lead I've had in that direction. Interesting, for sure...that looks kind of like something some now middle-aged Macs might have used (after the DA15 VGA-based connector went away, but before DVI made it onto all models - I think - Might be thinking of another sort of proprietary mess). It is worth noting that the use of this specific 20pin connector in the luggable computers dates to 1996 if not earlier - which may predate DFP...
(also, I recently obtained a 286 luggable whose monochrome LCD uses a 20 pin ribbon. However there is a separate power cable, plus it is substantially older, so the pinout is assuredly different and kind of irrelevant here. Just saying that "20 pins" is not a reliable indicator of anything, much to my frustration)
Part of the reason why I post (and take tons of pictures - but note my website is currently down due to a spectacular hard drive failure; my Dolch pics are mirrored somewhere else though and Google should find em for you if you want them) is to hit high on Google results, particularly with kind of obscure items. The Dolch computers are actually in an 'off the shelf' generic chassis, but Dolch is by far the most common brand of computers in these chassis so it's the easiest way to refer to them.
In any event you've definitely picked interesting boxes to play with. It would be somewhat off topic for this website, but I'm sure I wouldn't be the only 'geek' interested in following any 'hacking' you do to them in the off topic area...and I'll try to do some research once I have some free time (a valuable and rare asset recently). I do know the easiest solution to my problem is to simply get the PCI single-ribbon 20pin video card, and I think I have one lined up.
Cheers