Looking for software to publish on my self-hosted wordpress sites

Hello,

I'm looking for software that uses spintax articles and can publish them into my self-hosted Wordpress sites. My requirements:

1. Hold database of 100 wordpress sites with credentials
2. Generate up to 60 articles from each spintax article and publish them eg. 6/day.
3. Is cheap (~$30) or free.
4. Is mostly bug-free and I can add new articles fast.

Not requirements but nice to have:

1. Uses XMLRPC instead of "human interface" to log in to my sites.
2. Shows generated articles that'll be send so I can correct errors.

I don't care if it publishes them all at once as a scheduled post or publish them gradually. I don't care about the platform it works on.

Thank you. I can code it myself (I just want to avoid it since I'm pretty sure something like this already exist).