Actually, these are not THAT hard to find... you just need to know what you are looking for. These are the RJ-22 (RJ22) connectors. It's good to know ALL has them! It is true that not all stores stock the RJ-22, and now YOU have the reference number. Thank you ALL for all the parts you have supplied me for years and years!
Grab some of these while you can. If you have a business where you have a number of phones, you can save some $$ by repairing your own handset cords, instead of buying new ones!