OK, so I jimmied up a solution using metal tape similar to the above, after a few months it broke off, so I fashioned a second one, a little sturdier, that one lasted about a year before it broke off mid-commute, causing me to lose my blinkie forever -- with a pair of rechargeable AAA!

So warning to anybody that tries metal tape for this; check your tape periodically (monthly?) for cracks and replace. Make a handful at once, so replacing is quick. The problem (for me) is that with the light sticking out like that, it gets bumped/bent almost every time I flip the bike upside down for maintenance. Eventually, the repeated flexing causes breakage.