I've run V-levers on calipers before without an issue. The key is to keep the pads further from the rim. Then the extra pull gets used by the extra distance between the pad and rim. I'm running a Tektro R559 caliper on my Speed Uno with a V-lever and it works as it should. Granted the ideal setup is with actual short pull levers, but that doesn't mean you can't use them.

I'm eyeballing the Tektro RL740 at the moment. The quick release would be perfect for the brompton brakes, since they don't have a quick release built in. Would make wheel removal a bit easier.