Yes, the 278mm rotors fit my 15 inch wheels. I have the 12 spoke ones that come with the touring group option. Should fit the 8 spoke wheels as well. The SVT caliper brackets could be purchased from several sources. 1) Try the classifieds on this site for some one who has upgraded their SVT calipers to aftermarket etc. The mounting brackets are part of the SVT caliper but can be swapped over to the SE caliper without disconnecting the brake lines. 2) Also, BAT will sell you the calipers alone or in a SE to SVT upgrade which includes caliper brackets and 278mm rotors. Go to the BAT site and download the catalog. 3) In addition, check carpart.com for SVT calipers. 4) Of cource there is always the Ford dealer although I don't know if they will sell the bracket alone without the rest of the caliper. This is the most expensive route.
Hope this helps.