I got a response back from ebooks.com:
There are a number of distributors, or ‘aggregators’ who will work on your behalf to help market your books and reach a wider customer audience. Please note, however, that a number of these organizations actually charge authors for their services. I have listed a couple of companies below, who you may like to contact:
Lightning Source https://www.lightningsource.com/
Content Reserve/Overdrive https://secure.contentreserve.com
I hope that this information helps you in some way. We do receive numerous requests from authors and small publishers daily, asking us to list individual titles. Unfortunately, as our policy does not allow us to do this, suggesting distributors and/or aggregators that you may like to work with is the best way I can help.
Please note that we don’t work with third party aggregators to source ebooks at this time.
Now that’s interesting…Smashwords isn’t on there.