Coming to the conversation a bit late:
I am currently using three portrait lenses with 11x14, two Dallmeyer Petzvals and a soft focus Verito.
Of the two Dallmeyers, I prefer the slightly longer 22" f4 (5A), but the shorter 19" f6 (5D) gets used more often since it is significantly lighter, and requires less bellows. Even with 38" of extension, I often run out. I have attached two photos, the first taken with the 5A and the second with the 5D.
I have only just started using the 18" Verito. Its a much harder lens to get to know. I have been surprised at the results, as they don't always match what I see on the GG. Other soft focus lenses I have used include a 16" f3.5 Wolly Varium, a medium-soft triplet which I like quite a bit.
Another option are Tessar types. The f4.5 variety would probably be great, but I haven't found the right one yet. I have also used my 450 Nikkor-M for portraiture. Its a great lens, but a bit too clean and clinical for most portraits.
All this said, you are best off seeing what you can find and afford. The Petzvals which will cover plates this big are uncommon, and are selling for large sums of money (a big Darlot which would easily cover 11x14 sold a few weeks ago for over $900). The most common is the Dallmeyer 5D, which comes up for sale a few times a year. Also the Wolly Vitax with the 20" front element are often available and relatively affordable.