I second the recommendation for sealed/acoustic suspension speakers. The obvious choice for high-end sound is ATC (various models of differing sizes and costs).
I have a pair of passive ATCs (SCM12 Pros) and find their sound very impressive. They're not reactive to placement to nearly the degree most ported speakers are.
In your setup you might get away with a downward firing port, in which case there are multiple models to choose from. I read rave reviews of a new Polk floorstander with downward firing bass ports: