I came across this video and I was going to skip it, but then something made me watch it.  I am glad i did, this is  a pretty cool idea a long time coming.  Basically its a flush trim bit that has a bearing on top or bottom.  it comes with three bearings so that you can adjust it yourself.  I like it because it saves you time in chucking up a new bit, and it saves you money because you do not have to buy numermous bits.  Here is a summary of this short video, I can only supply the link since they do not have the code available to embed it.

• 4 bearings
• Flush trim
• 1/16″, 1/8″ 3/16″
• Makes something similar to a rabbet, great for raised panel work.
• carbide blades
• http://www.youtube.com/watch?v=hbA4DDAeC5I&playnext_from=TL&videos=moN5TJf3jB4&feature=grec

This really is a pretty neat idea.  You can see the Rockler Flush Trim Bit here
Avoid a tedious setup when you want to trim precise amounts of wood off doors and large panels. These kits use razor-sharp shear-cutting bits along with different bearing combinations to remove exactly 1/16″, 1/8″, or 3/16″ of material in just two router passes—all without a straightedge! Each kit includes one carbide router bit and five bearings to set up the various depths of cut. The Small Bit Kit is perfect for trimming stock up to 1″ thick, while the Large Bit Kit can handle doors and panels up to 2″ thick. Click the “Videos” tab above to see how this kit will save you time!

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