Of my two Ridleys that i race (40/46T front, 38/44T front) both 130b, i would like to use a 28/40T XT crankset for some of the steeper climbs in the area for training and riding. I do not want to change cassettes (12-27T) and i am running SRAM Force rear derailliers and shifters. What front deraillier would work? Thanks

Does you frame require a braze on mounted front derailleur? If NOT, then you could go for a sram XX band mount front derailleur, it would be ideal for those ratios. If it does take a braze mounted derailleur, you may run into trouble. The XT crank rings are likely too far from the frame for most road front derailleurs to reach.
Does your Ridley have a threaded bb shell, or is it a pressfit? If it is threaded, you could juggle some bb spacers around to bring the rings closer to the frame.