Not cheap but depending on your goals this may be an option.

Luggage straps for Datsun 240Z | DATSUN 240z | JDM CAR PARTS

Holy smokes $200! There is a set of used straps on eBay (including the hardware) for $14 that are just begging for a refresh. I think I have found an alternative to winning the lottery...

Oh come on, a "special hand made item with Japanese Patina" is easily worth $200 bucks!

Oh look, my first customer - and I don't even have to incur shipping charges!

Time to turbocharge the 'ol Singer...