Barker Microfarads in Hillsville (VIRGINIA!!!) makes electrolytics on the old Sprague Atom equipment. I'm not sure if they provide Vishay (sprague is only a name, not a manufacturer anymore) with caps or not.
There are a few boutique manufacturers making FP-style electrolytics in 450V-600V values, but most are available only from audiophile suppliers. AES has some.
Sprague was busted up years ago, with SBE maintaining the manufacturing, and Vishay buying the sprague name. SBE retained the orange drop trademark, and made them under their name and Sprague/Vishay. Recently, SBE sold the orange drop line to CDE, who now markets and makes them exclusively. My last three batches of 225P and 715P's all had a China country-of-origin, so the made in USA orange drops are no more. Strangely, SBE still holds the trademark.
Also of note, Virginia also has a ceramic disc manufacturer in Hampton (Maida) making disc caps and more. You've seen them - MDC is the brand.
Cheers,