These are eBay "completed" listings:
SPF 1889 Pearl Orange (I like, but I'm sure you can paint it too). $50,000 no bids:
Shelby Cobra Mkiii | eBay
SPF 2739 sold for $47,000:
Shelby MKLLL Cobra | eBay
SPF sold for $44,000, 460, 8,370 miles:
Shelby Cobra | eBay
Seriously, there are plenty of other SPF's listed, but not sold in the 50's and above. IMO, mid-$40's SPF is definitely possible, if not highly probable.