you know what, take advantage of the situation & use the lower height of your ceiling to make your speakers a line-array-like speaker. Line array speakers use the floor & ceiling to make them appear as an infinite baffle speaker. So, if you get a speaker with a radiation pattern that can make use of the floor & ceiling you'd have a fantastic soundstage height (& depth if you do this right). Line arrays do not have to cost a fortune (but they can). Check out VMPS speakers & those from Selah Audio:
http://www.vmpsaudio.com/
http://www.selahaudio.com/id73.html
http://www.vmpsaudio.com/
http://www.selahaudio.com/id73.html