What can I substitute for lady cream peas without noticeable flavor change?
Camellia brand has a store locator for it's products and the OP was able to find the lady cream peas at a location close to her.

For anyone who isn't able to find them, butter peas are a good option. I've seen them fresh, frozen, and canned. Other acceptable substitutes could be cannellini (white kidney) beans or great northern beans, although great northerns are not quite as sweet. Both of these should be available dried or canned. However, if you are to prepare them without salt, I would stay away from canned.