Alright, so initially I ran into the typical problems associated with this setup (only two screens worked at a time, passive adapter does nothing yadda yadda). My problem now is that only two screens are COLOUR. I went for a DP->VGA adapter based off a youtube video and the fact that they can't MAKE unpowered VGA adapters. My centre display is an HDTV using the DP->VGA adapter and the two monitors are using DVI. The third monitor hooked up always pops up as black and white however.
Latest drivers. The only two things I can think of are that I have to use an active DP->HDMI adapter instead of VGA or that the radeon HD 5770 cannot handle three displays... but the latter shouldn't be right. Others have done it and dropping the resolution doesn't help.