I have been having quite a time getting rebuild kits for my Fords/Mercs lately....I got to thinking...usually I only need the cups on the inside, 1 1/8" and 7/8" (front and rear) does anyone sell them by themselves? Like just a box of cups? I just got hit on wheel cyls when mine I honed out and cleaned up, just needed cups.
Have you tried a parts store? My small town has at least four different parts stores that will sell me an individual cup of any standard size. Look at a NAPA.
Yeah just got done with it, there are a few more I can check out tho. I have one parts store that is the ****, and I never use any others. I should check out a few others.
In a pinch you could always try and locate an old shop that does brake jobs. My old boss use to buy boxes of them.
Try a Car Quest. the local one here just north of Allentown got just the cups for me last year....it might take a little digging, but if you know what diameter they shouldbe able to help you. Good Luck