They occasionally pop up on ebay. Other than that I've yet to find a place to purchase dust bags separately. LP has various sizes available on their website for purchase. Wouldn't that be a great idea to suggest to Kooba?
Ebay doesn't allow selling dustbags anymore. They took one of my auctions down and when I called to ask why they said it aids in the selling of fake bags. Someone might try to sell a fake bag hoping a real dustbag makes it look better.
Kooba40: A few days back a member posted in either the Handbag forum or Deals and Steals forum that they had a source for plan white dustbags. You may want to do a search to see if that's a viable option.
A friend of mine makes wonderful generic dust bags. She will do them in any print, any size, any type drawstring. Plus they are reasonably priced. I bought some linen fabric in a cream background that was covered with all different style and colors of bags. Sent it to her and she made me a supply of them with double drawstrings (like on the Kooba bags where you pull from each side) in the different colors that were in the print. They are just fabulous. She sells on ebay as "brendaruth". Here's a link to one of her listings. She's become a friend and I just contact her direct now when I need something and she whips it up for me. Anyway, here's the link: http://cgi.ebay.com/Dustbag-Purse-B...ptZUSQ5fCSAQ5fWHQ5fHandbagsQQsalenotsupported
Lexie is right about the dust bags on ebay. No branded ones anymore. In fact, one day Brenda found that ebay had removed all her listings. She about freaked out and called them. She was told they were against the new policy of no branded dust bags. She said that hers were generic - no brand - she made them herself. After much arguing back and forth, they said their decision would stand and if she tried to relist them, they would terminate her membership. She was so upset she switched over to Bonanzle but unfortunately, there was no traffic. She only sold a couple of bags. Then, out of the blue, ebay contacted her and said they had credited her account for the listings they had pulled and she was free to relist them ... that she should consider it "an educational experience". She had to relist them all from scratch. Thank goodness she saves a copy of her listings so it didn't take her too long to get them back up. She really felt like saying "experience this ... " but that's where the traffic is. If anyone wants to contact her direct, PM me and I'll give you her email address.