You're likely to need a heated chamber to print without warping issues. Ideally the heated bed should be above the glass transition temp it the polymer has a sharp transition. Chamber temp is a little less defined. Few in the RepRap comunity go that far, and it will require careful design to avoid over constraint and cope with thermal expansion. For the sort or temperatures you're looking at for DIY I would look at building the printer into a second hand oven. All steppers and electronics will need to be out of the chamber and if you're looking at temps over 80 you'll need to looks at the spec sheets of everything to ensure they'll survive the elevated temp and not leak out lubricant etc.
Given the cost of the target market, and that if you are planning this for a company proving compliance with PUWER won't be a small exercise I'd suggest a commercial machine capable of working with PEEK isn't as expensive as it first seems.
All that said it's the sort of project I would love to have a crack at with costs covered! :-D
