What are you after- if it's just an LED mounted on a star (or unmounted), then the internet is still your best bet for a Q5.
Cutter Electronics in Oz usually has Crees. Dealextreme.com has the Q5s listed for $9 including shipping (though they are a bit random with shipping times). Getting a single LED locally would probably be more trouble than it's worth- I've had a search before and turned up very little besides a possible electronics place out around Cheung Sha Wan or further.
If you're after xenon bulbs, I'm not sure. I've only looked at LEDs.