I just use a Guide Series vest from Gander Mountain. Less expensive than a 5.11 or Wollrich, and serves my purposes nicely. It has four pockets on the left side (one zippered), three on the right, cartridge carriers on both sides, and a big, zippered pocket across the back with three separate compartments. It doesn't have Napoleon pockets, though. The other drawback is that the side adjustments are inside the vest, not outside, and they use metal "O" rings...quickly cut out so they didn't clank against my gun.
If your were up at Pruett's store on Huffmeister, I assume you go the Gander at Hwy 6 and 290. Locate the wide east-west aisle between the gun safes and the field clothes, and these vests are near the corner of that aisle and the aisle that faces the guns and ammo area. (Suddenly, it strikes me that I'm there far too often...
)A lot of the Gander Guide Series stuff comes in extra-tall, but I don't know about the vests. I don't think 5.11 or Woolrich come in XT, either. But they're all cut pretty long. I just checked mine and, on a hanger and measuring from the center of the shoulder, it's 35 inches long, about three inches longer than my sport or suit coats. I think they go up an inch in length for each step in size, so you could probably try one size larger than your normal if you needed to pick up extra length.
For IDPA, when you stand arms outstretched at 90 degrees, your concealment garment has to cover your weapon, mag holders, etc. With a vest, unlike a jacket, its hem really doesn't raise when you lift your arms. My carry is a full-size 1911 OWB, and the vest is an XL; based on my height and the length of the vest, my guesstiment is that you'd be IDPA-legal concealed up to 6'6" or 6'7"; so a 2XL up to 6'8" or thereabouts. Carrying IWB should buy you another three inches or so.
If none of that works, I don't think it would be too difficult or expensive to have a local place that does alterations sew on a double-thick border that matches the canvas of the vest.
Shoot safe and have fun!