I don't ride at night so I don't need a major beam, just a high-intensity blinky.

Got the headlight version of this from the 'bay and rode with it for the first time today:

Cycling Bicycle Bike 3 LED Front Tail Warning USB Light 4 Modes White Lamp | eBay

Seems to be exaclty what I need and for well under ten bucks; let's just see how long it lasts...