There are long reach dual pivot brakes.
https://www.amazon.com/TEKTRO-Bicycl...lpo_200_bs_t_2
https://www.amazon.com/Shimano-Reach...f=pd_sbs_468_1
I presume the longer the reach the less power, but they should still be able to stop you. However, that may be a reason not to go with smaller wheels if you're already having troubles with the brake reach.
If you have shop access, you could braze on your own canti bosses, but it gets to be a lot of work.
CANTI AND "U" BRAKE BOSSES :: STEEL SMALL PARTS :: BRAZON/SMALL PARTS :: Nova Cycles Supply Inc.
There are also canti adapters... I'm not sure about them, but it may be possible to rig something up.
https://www.danscomp.com/products/48...ake_Plate.html