This Stronglight tandem crank comes stock with 51/39/30 chainrings and a 110 BCD, and it appears as though you can swap out rings for a small additional fee as well:
http://www.spacycles.co.uk/products....id=m2b2s109p15
Stronglight does make a 110 BCD 53T chainring too:
http://www.spacycles.co.uk/products....d=m2b2s149p296
Any cheap, flat 26T chainring will do the trick for the rest.