Tracked down a 1/16" slot cutter for my router. This is a hard bit to find! Found one at a local Lowe's for $16 (with tax). They're $20 + tax at Home Depot. So far, this has been my general experience with prices at Lowe's vs Home Depot. I'll use this bit to cut the slot around the edges of the cabinet so I can insert the t-molding.
In the image, the distance B is the 1/16 edge that will cut into the plywood.