Couple of options.

1) Get a rack adapter for the blinky - it will bolt right in where the reflector usually goes. Most manufacturers make one, they just milk you $5 or so instead of tossing a half-dollars's worth of plastic and bolts in the box. I like my rear light here, as I can pile stuff up on top of the rack, and still be seen at night. (And I never set it to blink, but that's another flamewar for another time.) Peter White makes rack adapters if your rack doesn't have a reflector mount. (Cheapest things he sells, too.)

2) A small handlebar bag, like the V.O. Baguette, or Topeak Handlebar DryBag for something =really= small.

3) A small "triangle" bag that mounts inside the frame, M-wave Triangle pack, or DIY.

4) Get a fender-mounted tail light, like the Spanninga SPXb.