I love finding old answers...
I just tried importing my bookmarks (with MyBookmarks, free on android market) into Dolphin. I have 1600 bookmarks. Yes, I know...
Anyhow, I didn't find them. Tried 3 times to re-import them. No good. Then I remembered that they probably showed in the stock browser. BINGO! Almost 5000 bookmarks.
You saved me a TON of 'select - delete - confirm deletion.' Thanks!
Now I'm off to pare down my bookmarks and try it again.
Dan