I have been trying to find somewhere where this is possible but can't. Then I thought if somebody created 100 directories on 100 domains (sharing the same database) and then offered submission to them all for $20 they could make a fortune. As long as the sites were slightly different so they were not caught in a duplicate content filter it could work. The sites could all use co-op and the weight could be spread between the 100 sites. Each site could also accept submissions just to that 1 site for free to keep the content different. Would this work?
In Theory it could work, however in practice you'd be hard pressed to convince google of not seeing the sites as duplicates, seeing as they would all have the same inital data. Even changing the design of each directory would be time consuming if you done it 100 times over, and reviewing the free listing submissions for 100 sites would also take a good deal of time unless you just auto approved any old site, making your directories less valuable. Also, the cost of hosting and domain names would be be in the region of $700-$1000 a year. Finally, you would have to have some sort of value, be it pagerank or visitors, to make it worthwhile to be listed on these directories, as I personally wouldn't spend $20 on submitting to 100 PR0 directories. Trying to get at least a PR4+ and/or 100+ visitors a day 100 times over is a lot of work for not a great return.
To rain on the parade a little more. Google's latest patent states that they will take into account the domain registration to look for spam. All of these directories being owned by the same person is likely to raise a flag. Once one got banned they probably all would.