You could get 3 pairs of these which would be US$990 ($330 each) -
http://www.axiomaudio.com/m3ti_main.html
Then a center channel for US$255 -
http://www.axiomaudio.com/vp100_main.html
That's US$1245 altogether.
Research the company on sites like the forums at audioholics - they make excellent speakers and they give you 30 days in home trial - if you don't like them (which will be impossible) you can send them back.
Blu-ray.com member BrahmaBull has the speakers I've mentioned (bookshelves) for his fronts, so you can get a personal opinion on them from him. I've listened to the Dave and Tim Blu-ray Disc at his house on a TX-SR605 listening to the 24/96 TrueHD track and they are a very accurate speaker with really good separation and imaging.
Alternately you could just get two pairs of the bookshelves and one center and spend US$915 and then get another pair for your 6th and 7th channels once you can afford them.
If you don't have 2-3 feet room behind your main listening spots then there's not much point in going to 7.1 over 5.1 if you're getting good speakers, which these are.