I think this is a great idea and I may adopt this line of thinking
I LIKE IT!!
Seconded. Great idea.
Thirded...
I currently have a 2007 iMac in which I upgraded the boot drive to an SSD (OS and apps) and replaced the optical drive with a second internal hard drive (data). It has extended the life of the computer, but when its time to replace it 3 or 4 years from now, I might also go with the mini + dual display option. The setups in this thread are inspiring.