I am a catalogue junkie, even though I never buy anything, and I have never seen any advertised, that doesn't mean there aren't any out there though.
Pink, orange, yellow, green but not purple, I am wondering if purple would actually be as hi viz as the other colours? If you fancy it though,and can't find one, just get yourself a purple exercise sheet, buy some yellow or reflective tape (ebay, cycle/sports shops) and sew it on! Easy!