I forgot about PRstorm actually. It works great in your case, because you aren't going to send more than 20-30 links to each domain on your list. More than that, may perhaps raise red flags. But what you would need to do is to mix some PRstorm links, some bookmarkdemon links, some autopligg links, and if you'd like to, xrummer links in the mix (would be overkill perhaps, but if you can spare the budget, it's always best to have more)
For autopligg, it's actually a story submitter. You write some text, and include an url in your blast, think of it as an RSS aggragator I suppose?
hope that helps.