I need to build a couple of doors for our bathroom cabinets (about 12" wide
x 30" high), and am thinking of putting mirrors in place of the usual wood
panels.

I was thinking of building a frame, with a rabbet in the back for the
mirror to sit in. Then a second rabbet, closer to the backside, would
extend out a bit further into the frame. This would allow a plywood backing
to be screwed to the frame, thus securing the mirror and protecting it from
damage when the door is open. It would also allow easy replacement of the
mirror if it should get broken.

I recently received a catalog from Pricecutter.com, and noticed a "stepped
rabbet" router bit. It appears to do exactly what I'm thinking of, but I've
never heard of this company before, or seen these bits anywhere else.

So, I'm wondering if anyone has used these bits, and am also interested in
hearing in any alternative approaches I might consider.

Thanks,

Anthony