The best stern and p/s lights...

I have mounted the Scotty sea light on pole to rear of my kayak via scotty round flush mount. I chose round mount because tube is capped at bottom. Cost is approx. $40. I chose to mount on kayak instead of just strapping to milk crate for more customized look only. With the goop I'm not worried about large amounts of water (or any for that matter) getting inside.

http://www.clavey.com/ky_acc_fish_sea_light.html

For port/starboard lights I chose unfortunately the "kayak navlight", which costs $60...unfortunately. All this consists of is a badly designed case and two tek-tite MarkIII 1-led stick/led lights. You should just purchase red/green MarkIIIs yourself and save $20.

http://www.tek-tite.com/src/product_info.php?id=31

I could've used 12v lights for this and had a totally custom look for sure, but I decided in favor of removability. LEDs last forever anyways, so battery drain is pretty much a non-issue.