Greetings From Twigital
The list you provided, we have worked on all but now-a-days only 1 site provides the approved link that is - reddit.com.
if you wish we can submit the sites on the list you provided, but can't commit to have approved link. We also have a good PR list of social bookmarking, if you wish we can share with you.
Lets discuss in detail and get started with work.
Thanks
Nihal
Twigital