How about a list of the true grails or White Whales? Not personal grails like acquiring an Imperial Blue or the grill nicknamed the white whale, the Plainsman, which has been found a few times (and which I've personally, stupidly, let one slip through my fingers) but those grills that are so rare, they've never been found or spotted outside of catalogs or posters.
Off the top of my head, I can think of:
George's Original (though I think one member saw the base, no lid, to one at a flea market once).
A Wishing Well (though I seem to remember (@Harris maybe?) saying that one existed in the Atlanta area.
An Ambassador, or any Yellow Ochre kettle
A Barrel-B-Q
The Penthouse
The Flamenco(?-I know that the cast iron stuff gets a little wonky because of the other manufacturers used, but I don't think I've seen one of these yet)
What else is missing before the WKC collects (or at least has seen, in the case of the meat parts grill, which I don't think anybody acquired but was on ebay) them all?
For variants, I think the red fireplace and whatever size fireplace, in red and black, that wasn't bought off of ebay, and a Ranch rotisserie might be on that sub-list. Maybe a 26" C&T ring? I'm not including the Yellow Ochre as a variant but as an actual White Whale because I don't think anything of that color has ever surfaced, whereas there's countless red grills and old rotisseries, and at least 1 known fireplace.