No-name sealed aluminum pulleys I've bought on ebay (can probably be found locally, though, since they're basically generic) are suntour-sized, the hole that is, with shims to fit shimano derailleurs. That's an option. You could swap pulleys with any old suntour derailleur, like you may be able to find a vg (vt?) derailleur for nothing. It won't have the top pulley float but that's no big deal.

As far as indexing goes with a new derailleur, you're basically out of luck unless you find more-or-less the same derailleur. I have a six speed, XCD6000 drivetrain and basically my shifters are only compatible with the XCD6000 derailleur and the 6 speed "accushift" freewheel. Suntour made "regular" and "ultra" 6 speed freewheels, which are much more common, but my derailleur and shifters will only mate with the "accu****" 6 speed freewheel (luckily I have 2).

But I think- I could be completely wrong though- I think most of Suntour's 6 speed indexing systems were made to work with the ultra freewheels and just a few lines were made to work with the "accushift" freewheel.

So, how to find out which you have: http://www.sheldonbrown.com/cribsheet-spacing.html

Scroll down to find the cribsheet on cassette/freewheel spacing. If you measure and find out you have an "ultra" freewheel then you're in luck. I believe you would be able to use any Suntour 6 speed indexing, or possibly even 6 speed non-indexing (provided it was designed for the ultra freewheel) derailleur and it would index with your current shifter. If you have the "accushift" freewheel then only a 6 speed accushift rear derailleur will work.

Long story short- finding some pulleys would be the easiest thing to do.

I could be wrong on some of this though, you might want to ask this question in the mechanics forum.