is A. chrysantha a suitable one? Cant remember if it is double or not.

Yes indeed...I breed them! And not only yellow doubles but red and yellow doubles, pink and yellow doubles...nearly black & yellow doubles...purple & yellow doubles....tempted yet????!!!! here in UK there are 2 National Plant Collections and they are both here at Touchwood in Swansea...come and visit! To see pics of my doubles with yellow in check out the aquilegia seed page on www.touchwoodplants.co.uk