Hi Dougal,
The item bid of $512 USD still leaves a lot of work ahead!
I inquired with Steve of Cape Sport about making these a few years ago, his guesstimate at the time was about 1000 sterling a pair, equates to about 1500 USD, so take off $500 leaves $1000, making the L/R moulds say $200, each window say $100 leaves $600, purchase of rubber bits, say $100 leaves $500, straightening frames and fiddling say $300 and how good is the resultant effort?, leaves $200, rechroming and re assemble say $300, your going backwards, and this doesn't include possibility of having to sweat off and reset pegs or the fact that they are not a perfect spatial match to your windscreen/door top profile in the xyz planes
Cheers