The general concensus in the classic triple forum is Nology. They are around $70 each.
http://www.nology.com/profiremotor.html
I replaced all my coils with Nology after I had two OEM Gill ones go bad; haven't had any issues with them. The nology coils are actually made by PVL which was the original OEM supplier until Triumph made the switch to Gill.
Part # is 152 001 060T
Description says "Bonneville America, Speedmaster, Scrambler
(needs 2 coils per bike)", but they are the correct coil for the carb triples also.
I'm running them on a Tbird.