Dmoz is now very hard to get listed. I think you can't find any service like this. I suggest you a better way that find expired domain that have listed in Dmoz in same niche and register it, do 301 redirect to your main site.
I agree, it's rare to successfully be listed in Dmoz, besides does it still count? All the people I know and associates in this business don't care about dmoz. Personally, I believe it as a false metric. Just think about it, would you as a user use dmoz.com?
Sorry about it, I mean many factors we think it's good for increase google rankings or other search engine rankings, are from experiences of other people. And they telling what they think it would be good to increase ranking.
However, in some case, it's not. So if you want to sure Dmoz listing or any other can boost SERPs, you should try it to have yourself experiences.