You might just need a good but smaller, more compact speaker design in a room that size.
For Ohms, I'd try the Ohm Micro Walsh Talls in a room that size first, I think, particularly if you already have a sub that might be added. Ohm recommends these mainly for more near field listening in a variety of room sizes I believe.
The Ohms are bottom ported though which could work against your desire for isolation. Placing them on concrete slabs or something similar could help. Loosely plugging the ports can be an option as well in more lively rooms that are less isolated naturally.
Both my larger and smaller Ohm Walsh speaks are located in my basement currently on a concrete floor with thin carpeting and padding and this provides an extensive amount of natural acoustic isolation.