David Silver Spares in the UK sells it It's genuine Honda but is still 22GBP US$ 33.66 - but I can't usually find anyone to beat DSS on prices. He has 52 in stock when I last checked.
http://www.davidsilverspares.co.uk/parts/part_7657/BTW My 400/4 (in my profile & still have it) was restored in 1986 and I got all of the hard to find parts from Dave Silver when he was operating from home, part time, (like a NOS rear fender for 10 GBP, Complete caliper inc. pads, bolts etc for 12 GBP !!!!!!!!!!) He's still by far the cheapest for new parts though, that I can find.
But nobody sells the plain chrome tank strip K0/Sandcast, to my knowledge . I know a CB750 Guru guy in the UK uses cut down Mini (car) wheel arch trim cut but I have not located it yet.