Spaz, I understood you would prefer to keep the speakers in the current position. I was merely suggesting to probe the room bass response before rebuilding the ceiling. It is very difficult to predict how the low frequencies will interact in a room. This is because bass waves have absolutely no problems to pass through walls and often standing waves are formed between the walls of different rooms. Consequently, it is best to experiment, i.e. just move the speakers against each wall.
Another alternative, that, in fact, will allow you to verify weather or not you can get good bass in the current configuration is to loan a good subwoofer and place it at your listening position (I recommend a REL Stentor or Studio). You can find more details about this set up procedure in my fist post in the thread "Are the JL Fathom subs really that good...." here on audiogon (see link below).
http://forum.audiogon.com/cgi-bin/fr.pl?cspkr&1219437689&openusid&zzNvp&4&5#Nvp