Mark- those diagrams are PERFECT! Great advice.

Klipsch makes IN-CEILING speakers for those who wish to have their surrounds mounted to the ceiling. There's even models with twin firing tweeters for that wide disperse sound. THX inceiling are also a reality nowadays.

 "In the mean time, my problem is that the only other place I can hang them are on a wall that is essentially in line with where one's head/ears would be while watching TV"

that'll be just fine. Remember that early side surrounds which were bipolar in design (speakers facing directly forward and backward) were also placed beside the listening postion. The very same occurs in a REAL cinema. Put them 1-2 feet above your seated head position (near low ceiling is ok). 

Do NOT attempt to 'hang' them on ceiling. the cabinets are not meant to withstand their weight in this manner and might disassemble, harming stuff on the way down. You wouldn't want that would you?

Michael

I'm sure forum members will be reading your posts for years to come.  They've helped me in the last year!  Thanks Michael.