Well, I've been thinking about this for some time. Ultimately, I think you may revise your opinion on whether or not one should worry about space and weight saving triple convertibles when you actually start moving an 11x14 or larger camera around. They big, heavy, bulky beasts and a couple of extra pounds in lenses really doesn't seem to make too much difference. However, I have always been attracted to the Cooke XVa re-incarnation and finally received my sets last week (two lenses - one in the shutter and one without - the extra set allows two extra focal lengh combinations).
The single set allows three focal lenghs - 311mm (12inch+-) - both elements; 476mm (19 inch) - rear element only and 646mm (25inch +-) - front element only. I haven't tested this lens yet, but these focal lenghs all provide coverage on 11x14 (i.e. no vignetting when focussed at infinity. The 311mm combination does not provide a huge amount of coverage but there's a little room for movements at f45. The other two combinations provide loads of room. With the extra set of cells, you can get a 273mm focal lengh (both rear cells) and 368mm (both front calls). The 273 covers 8x10 OK, but does not cover 11x14. The 368mm combination covers 11x14 just fine. I have not yet shot film with this lens, but will be testing these combinations later this week to check corner sharpness on 11x14 (with a 6xloupe on the GG it looked fine) to ascertain if this lens is going to work for me on 11x14 as well as 8x10 (I only contact print on these formats). One important detail - the flange focal distance of the 25 inch set-up is around 29 inches - you will need a camera with good bellows extension.
Early indications are that the lens will work very well for 11x14. Combine a single XVa with a 240mm Kowa graphic or Computar and you should have a fabulous 2 lens outfit which should cover a huge range of needs... The Cooke has gained a reputation as having the finest multicoating of any modern lens available - apparently unbelieveably flare resistant. Of course, there is that little ugly sticking point - the price!! But for close to $3000 you get what is essentially three very lightweight (average the total weight) lenses with awesome coatings - doesn't seem so bad....