Oy, thats a tough one. Long, narrow feet may be the most difficult feet to fit.
The Mid-Weight Boot
A few makers put out 13s in regular width. That would include Garmont with its Syncro Plus ($190), a solid, all-around backpacking boot. Or the Lowa Banff ($270), a really nice boot, with full-grain leather uppers and even leather liners. Very tough and sturdy.
So one option is to take a boot that doesnt quite fit, and then make the best of it. A good boot-fitting shop, for instance, will have tongue padsfoam inserts that you put under the tongue to soak up extra space in that area. You also can try after-market insoles such as Superfeet ($35) in the high-volume model. These are designed to replace stock insoles, offer more comfort and support, and fill extra space inside the boot. With Superfeet at the bottom, and tongue pads above, you might be able to make a stock boot fit.
Otherwise, my friend, its custom for you. The gold standard here is the Limmer Mid-Weight ($300 in stock sizeabout twice that for custom), a superb, rugged leather boot.