What was the reason you heard for going full tower?
The only thing a full tower would give you is more room for drives and room inside the case. If the reason you heard is because of temps thats not always true. Make sure you case has good airflow thru it and youll be fine. Just because a case is bigger doesnt mean its better.
As far as the power supply goes, look at the antec, emerex, and the pc power & cooling line of psu. Not sure on anyone exact model as I dont run sli (yet)
I recommend this one with another fan added to the exhaust location. I've tested it extensively, what we have here is an inexpensive case ($60 without window or power supply), and the added in power supply is fairly stout. I'm currently running one with a Prescott/SLI settup.
The case is very solid and among the quietest I've tested. The stock cooling sucks...but moving the front fan to the rear cures that, better still just add a fan.