I'm actually looking to do a quad build as well. I've got a Nano QX and a Taranis plus transmitter I've been practicing with, and a Super-X brushless on the way, but want to do a 250 racing quad based on the Blackout. I've got a spreadsheet going of what I need to pick up still.
FYI, if you're serious about doing an FPV build Simon, you're going to need to get your technicians (ham) license to do 5.8Ghz video. I've been passing the hamstudy.org practice tests, just need to bump up my rating to about 85% and take the test for real.