Sounds like you have already thought of just about everything. You can never get rid of all dust mites, just minimize their existance. Other options might include: * You can put down parquet wood flooring over a cement floor. * Oriental or other throw rugs arn't expensive and could be used. We got some 5x8 oriental throws for under $100 each in our bedrooms which we wash and set outside in the sun to help kill dust mites. However, our allergies arn't that bad. * Products like Nasalcrom really seem to help. We block the allergies at our noses.
Sorry bout my first post. I didn't have much to go on. You already implemented most of what I mentioned.