If you go that route, there are hundreds of 'Mechs with artwork whose variants have no specific artwork.
*I* definitely don't mean it like that; that would be more of a fan art project.
I think the...Games Unplugged?...I don't own them; but there were two issues which included art galleries for every variant then established for the Hunchback and Hatamoto-series.
What i am principally going for here with the Never-Seen is those units in BT which have been mentioned only rarely and probably not in great detail; but never statted out with a record sheet, limited, if any fluff.
Some of these will have no art at all; but my main goal here is to create an accounting and brain trust of the kinds of units that might go to fill XTROs and the handful of unit-entries in the back of new sourcebooks.
Like; wow. How cool would it be, if even as a photo-shopping we had someone going through the books and giving us representations of all the canon variants in art form?
Cool. But I don't so much need that as we once, needed at the time; stats for the Leviathan Jumpship. We have so few Jumpships in canon and the Leviathan kept coming up in odd references and sounded really neat from what we knew at the time. Now we have art, stats and fluff for the Leviathan JS and I think that's basically the ideal.
Something I added recently was a notation about the Dragoon's Ballistic-based Marauder II Variant mentioned in 3050 and attributed by the useless CASE in the wrong torso. We have art; we have fluff; we need stats. Headcanons aside.
So for a unique mech; we need stats and a record sheet. Maybe some fluff telling us how it came to be, even if only generally. For something like the Old-New-Old-New entries; we have art and fluff; we need full stats; at least a record sheet.
Some of this could be handled easily by the Devs if we had an official design program again; goodby record sheet docs, hello file-packs of various models that load and print from the program. Or I guess display on tablet for you non-luddites. But mainly, this is me kinda going to TPTB; hey! LOOK! You need something to fill five or so pages of that new book coming out? Here is a list of ideas, already established in canon, to one extent or another, once upon a time.
