If you don't absolutely
have to have actual Sprague (Vishay) -brand Orange Drop capacitors, Mouser (
www.mouser.com) has Cornell-Dubilier DME caps with 630V ratings with values up to 2.2 uF.
These are metallized polyester caps, and while I've never bought these in such high values, I must say I've been pretty happy with the ones I've used so far. I bought a bunch of 630V-rated versions (they're available in voltage ratings from 100VDC to 1000VDC) of these in several different values from Mouser a while back, and so far they've been nice. They're quite a bit smaller than Orange Drops-- the smaller size and the flatter shape of them makes them easier to fit in crowded areas (in my opinion). I like their overall appearance better too-- they're a muted dark brown-orange color that I think blends in more nicely with existing components in an old chassis or PC board a lot better than the bright-orange color of Orange Drops. They're also significantly less expensive. I don't know if their current handling is comparable to Orange Drops, but perhaps someone else here knows and/or has had experience with these..?
(Note: If you're trying to find these in the Mouser catalog (.pdf version is available on their web site), the Cornell-Dubilier DME caps are on page 671; they also sell Sprague Orange Drops, and they're on page 679)