In previous threads I've mentioned CD Wow but they tend to be a bit more mainstream than what you're after, though sometimes you can be surprised. But just lately they've introduced a vinyl section which I've been raiding lately - it is hit and miss but sometimes it is so cheap it's ridiculous, with no postage on anything (which anyone who has tried to import vinyl would know, it can be very expensive). Last night I bought Teenage Fanclub 'Grand Prix' for 9.95 and Smashing Pumpkins 'Siamese Dream' for $15. The other week Fleet Foxes lp + EP was going for about $15. New xx album for under $20. You've got to check back all the time because prices seem to change all the time, and if you subscribe to their email service you get discount vouchers almost every day. Oh and they now have T-shirts too.
But Red Eye sounds like it might be more up your alley
http://www.redeye.com.au?
Au Go Go in Melbourne used to be good too
http://www.augogo.comEDIT - don't think Au Go Go exists anymore? LL would know...
Missing Link
http://www.missinglink.net.au/Rockinghorse in Brissy used to be be great when I lived there, assume it still is:
http://www.rockinghorse.net/