To answer the question, Yes, there is a bit you can use for t-moulding with the dremel. That's how I did mine. You'll need the screw- on router attachment, and a metal slot cutting disk. I don't rememebr the name specifically of the slot cutting disk, It was around 15$, and it works great. The trick is to get the disk centered on the piece of wood you're slotting with the plastic router stand in place.
-PacManFan