A few years ago I built some of the plywood type you mentioned, cubical, like the ones used in Cornell's research on bee home-site preferences. These were mounted 15-20 feet up on tree trunks and did get alot of attention from swarm scouts. Unfortunately they seemed even more attractive to squirrels who'd gnawed the hole til it was big enough for their entrance/exit and fill box up with nesting material. Since then I have had good success with old drafty hive bodies containing 2-4 old frames with reject combs. I set them up about 10+ feet if I can, entrance facing south or east. Bees seem to like them if they are exposed but under a shady branch. For a lid I often use a scrap of plywood which is longer than the hive so it overhangs the entrance by 4-8". For a floor I use an old bottom board, inner cover, or again a scrap of plywood. You can drill a hole for an entrance or raise the box off the floor 3/8 " or so with cleats making an entrance at one end. Bees are attracted to the scent of these old hive bodies, which according to the research are about the right volume to attract swarms. (16 1/4 x 20 x 9 5/8", maybe a bit bigger) If you make bait boxes out of cheap/scrap wood, by all means construct them so they can hold standard frames, even if you have to stand them up somehow. Then when you do get a swarm you can just transfer them to a good hive, or at least be able to pull out a couple of combs to search for the queen. Then you can run her in to the new hive and you'll be sure of her whereabouts. If new wood you can rub melted old brood comb/propolis around the interior of the box to spread the pheromones around as well. Then just check the bait boxes weekly. I've had to empty one three times during one season - the swarms just kept coming! Locations? Try top of a shed, carport, tree house, ledge, whatever, preferably sheltered & up off the ground. [If you end up transferring some crappy combs from the swarm box to the new hive, you can keep these over to one side of the hive. Then after the bees have taken possesssion of the good quality combs you can replace the bad ones in a few weeks.] Just be SURE inside of box stays dark and dry, otherwise they'll pass it up. Best success for me has been locations at edges of wooded areas. It's quite a sight when you happen to arrive as a swarm drops out of the sky to take over your hive! Hope this helps -- Good luck.