Dell Optiplex 755 Mini-tower Motherboard Upgrade

I have a Dell Optiplex 755 mini-tower and I would like to upgrade the motherboard to support SATA III and the new iSeries processors.  I absolutely love the Dell Optiplex 755 case and it would be hard to replace it with something comparable.   Most of the cases out there look like UFO spaceships or crotch rockets.  The Dell Optiplex 755 case is quiet and refined without the unnecessary frills.

I am thinking of purchasing a Dell Optiplex 980 motherboard or a third-party motherboard, but I am hesitant to do it without knowing if the motherboard will be compatible.  I've googled all over the net and it's unclear whether the Dell Optiplex 755 mini-tower supports a standard BTX motherboard or a 980 motherboard.  Wikipedia lists all of the OptiPlex models (see http://en.wikipedia.org/wiki/Dell_OptiPlex), but it is unclear which models support standard motherboards.  It only mentions that "later" models support standard BTX motherboards.

Can anyone provide me with this information specifically for the Optiplex 755 mini-tower?  Also, is the power supply compatible as well?  I've read in a few boards that the power supply on some Dell models will fry non-Dell boards.  I'm almost willing to pull out the Dremel if I have to

Thanks in advance.