I purchased mine through Chai aka [email protected] this is the same vendor as seen on Ebay. For some reason the double-nut Single Flange setup he doesn't list on ebay at all. Ask him for a quote and submit a drawing for how you want the ball screw ends machined. This was what i got from him back in 2014:

1pc 2005-532.8mm overall length with 1pc DOUBEL BALLNUT AND end machined as your drawing(2pcs locknuts as gifts)
45 usd
1pc 2005-1013.7mm overall length with 1pc DOUBEL BALLNUT AND end machined as your drawing(2pcs Locknuts as gifts)
53 usd
1pc 2505-750.6mm overall length with 1pc DOUBEL BALLNUT AND end machined as your drawing(2pcs Locknuts as gigts)
59 usd
Sub-total
157 usd
DHL shipping
69 usd
Total
226 usd