This looks like a combo of the high output S360A and the W371A. We can use the line drawings of both provided by Genelec to estimate the size of the mystery speaker, or at least the width of the front baffle.
Assuming the screws are the same as those holding the woofer basket in place for the S360A and W371A (10mm), taking the vertical length in the photograph (which is not as distorted as the horizonal by the viewing angle), and measuring the diameter of the smaller driver mid-surround, it's about 10.5 times larger, which gives 105mm or 4.1". I'd say just over three of them could fit on the front baffle, which makes it likely that the 15" front woofer we've seen in the W371A is a good approximation. It could also be the 12" back woofer, but that does not have the folds in the surround. And then the 10" woofer in the S360A has a different surround altogether.
The front baffle could then well be 400mm or 15 3/4" wide, as with the W371A. I doubt it is a size in the between the latter and the 360mm or 14 3/16" of the S360A. That would be pretty inefficient from a manufacturing perspective and lead to costly optimization work as well for the designers.
So: a high output speaker with a compression driver, with two or four 4" drivers flanking the horn, front baffle 400mm wide. It would be really strange if it sat on top of the W371A, so it's likely a floorstander that's somewhat taller with another back woofer to allow the directivity manipulation we've come to expect. The W371A is 1108mm tall or 43 5/8" (3.6'), so taking a wild guess and accomodating for the size of the horn, let's call this one 1400mm or 55.1" (4.6') tall.
Front baffle looks like a different material from the sides. Might be MDF, like the W371A. The sides look like the same finish as the S360A, so maybe those are birch panels.
@Penelinfi Do you mind making another drawing using the above?