Oh, You Doorknob!

It is amazing to me how what seem to be small details can consume so much time. For example: the humble doorknob. There are people and entire companies who spend way more time than I do thinking about doorknobs. (And I have been stunned at what some of them cost.) But now I am fixated on doorknobs, and trying to find 2, or maybe 3, sets of doorknobs that come close to matching the existing ones, original to the house. Below is a picture of what is turning out to be a hard-to-find item. Doesn't look that special, does it? Any suggestions?