More evidence of an imminent annonuncement of a new Ryanair base in Madrid:
http://www.presstur.com/site/news.asp?news=6632
"
A Ryanair pretende operar a partir de Madrid para Roma, Milão ou Bruxelas."
So the list of potential destinations from Madrid Barajas currently stands at:
Granada
Canary Islands
Rome
Milan
Brussels