For flavor closest to a red kidney (and a similar color, but in a more rounded bean) I would recommend the pole variety "True Red Cranberry". "Brockton" pole (available from SSE) would be another possibility, the beans are roughly the same size as "Red Kidney". Don't know your zone, but both are early.

"Brita's Foot Long" (also pole) would be a good replacement for "Great Northern", but the only commercial source (in Canada) will not ship to the U.S. Several members of this forum offer it for trade, self included.

Never was a big fan of Navy beans... probably from all of the time I spent on those big iron canoes. ;-)