Just want to put my voice here too:
I upgraded from V66 to 67 and my Speeddials are gone too...
What strikes me: I seem to have now 3 Computer with the same name (The one where Speeddials disapeared)!
For some reason Opera seem to think it is a different computer and places the speed dial in a separate folder.
Seems to have also happened on the previous upgrade, since I found some more speeddials in that 2nd folder as well. Opera seems to be copying the speeddials in the new folder, but seems to have been interrupted from doing so and therefore some or all speeddials are missing?
Anyway, Solution:
Dragging them over to the "new" (same name) computer at least solved the Speeddial issue for me.
But it is not nice.
It was scary (some research was saved in speeddials and sync seems to be also not working right...)