Evil trick I found out that works great.... my crappy old vacuum! We have an old Dirt Devil vacuum that can't pick up anything with the main vacuum, but has all sorts of attachments, including an upholstry brush. We use said brush on Jake, and HE LOVES IT. In fact, he's the one who started it! I was vacuuming out his kennel, and he came up to me and laid down (ready for grooming!) I was a tad leary, since the brush was hooked up to the vacuum, but since the suction wasn't super strong, I gave it a try and it WORKED WONDERS. Filled the canister of undercoat in 5 minutes without damaging guard coat.
Wouldn't try it with a Dyson.
GSD: Jake. (rescue)
Labrador Retriever: Spookie (adopted from local shelter)
Bengal Cat: Starbucks (rescue)