When I posted this article, the world pretty much wiped out the inventory. http://cheesycam.com/quick-release-adapter-it-is-compatible-with-manfrotto/
Just FYI, if you haven't been able to get your hands on a Manfrotto Compatible Quick Release adapter, they are back in stock. They are perfect if you have the need to quickly move your camera from a Manfrotto tripod, over to another rig like a Slider, or Crane.
Quick Release Adapter + Plate (not Manfrotto branded)
If you're just in need of the plate itself, they have that available too (again not stating Manfrotto Compatible)
Sliding Plate (not Manfrotto branded)
Quick release adapter questions are always coming in, and I really have no answer except for the Manfrotto RC2, 357, or 577. They aren't cheap, but if you're already using a ton of Manfrotto products these adapters might work into your workflow.
Manfrotto 323 RC2 Rapid Connect Adapter with 200PL-14 Quick Release Plate - Replaces 3299 (Black)
Manfrotto 357 Rapid Connect Adapter with Sliding Mounting Plate 357PL - Replaces 3273
Manfrotto 577 Rapid Connect Adapter w/Sliding Mounting Plate (3433PL)
Ok, so I did some additional searching and found this new QR adapter. I actually ordered it a while back, but it took it's time getting here. I didn't wanna talk about it until I knew the real build quality. Oh how many items go unsaid on this blog, you have no idea. Now that it's in my hands, it's actually very nice, and i'm ready to share this one to you guys. It's a solid metal build all the way around with two bubble levels. The whole adapter is a fairly thin profile and comes with a snappy spring loaded release clip. Careful, when you lock the plate in place, that clip snaps back pretty quick. I caught my finger on it and it's pretty strong. It's a wide base, and I use it to cover the entire base of my battery grip. I find it feels like a more solid mount this way, but if you're not using a battery grip, you may want to use it the long direction to get to your battery compartment. It's a very nice and cheaper solution than those Manfrotto adapters, especially for all the stabilizers and other DIY projects you might be working on.
Cheap Quick Release Adapter + Quick Release Plate