Today I got a call from someone who said they had a swarm of bees they needed to have removed. When I arrived, the bees were in a large oak tree that the wind had blown over a few days before and the man wanted to saw the tree up and wanted the bees out of the way. The tree was about 30-36" in diameter where the bees were. They were coming out of a crotch between two large limbs and also a knothole about 2' below. At the time I couldn't figure out how to get the bees out of the tree so I had to tell the man that I couldn't help him.
When I got home I looked at the bee-vac plans on this site. Basically you need a container to hold the bees and someway to regulate the air flow. I had a shop vac and was able to find a vacuum hose from an old vacuum sweeper. With these I fashioned a regulator box that was about 6"x6"x3" with one side curved to fit a 5 gallon plastic bucket. The regulator had a hole for the shop-vac and another side hole with a baffle that I could open and close to regulate the air flow. On the curved side I put aluminum screen to cover the hole into the 5 gal pail. On the other side of the pail I made a hole that would accept the vacuum sweeper hose and another baffle that I could close the hole with when ready to transport. (baffles are 1/8" plywood with a screw so the plywood can be slid over the hole to open and close it) I didn't use any caulk but did cut the wood pieces for fairly tight fits. The whole rig took about two hours to build. I can regulate the air flow into the pail from very gentle to strong.
I wasn't able to use the bee vac because when I went back the man had already killed the bees. I had planned to vacuum the bees that were on the outside, and then cut out a wedge to have access to the cavity inside the tree. I also have two three foot vacuum extensions so I should easily be able to reach bees 6-8 feet high from the ground.