no idea if they still sell them (I bought mine a few years ago), but HPE in the UK makes a very nice handbrake solution which uses the same Brembo master cylinder that you see on a lot of OEM rear brakes. It has a very flexible mounting solution (can mount via the handlebar or fork leg) so you can probably find a solution for your bike.
They used to sell them via eBay, but you'll probably need to call/write them:
http://www.hudsonperformance.co.uk/contact-hpe/
Then I had Galfer make me a custom brake line.