A fellow has designed a triple doweller as an alternative to a Domino and is looking for feedback:
Link to video if it doesn't load
Link to video if it doesn't load
Something that caught my eye when he was demonstrating it, it doesn't appear to be all that easy to hold still and the way it was kind of wiggling around you're going to end up with oblong holes.
Regarding the cost, it would seem the Triton Doweling Joiner would be a much more accurate and cost effective solution.
Triton TDJ600 Doweling Joiner
Drills two precise holes in a single plunge for fast, accurate doweled joinery.www.rockler.com