You should look at it as gift from above. Shorting LULU at this level is suicidal. Unless you strongly believe the markets will tank from here, and by tank, I mean DOW breaking the 12K support. That kind of technical breakdown would definitely drag LULU down with it.
If you want to short stocks with crappy fundamentals, the financial stocks have bounced a bit and are ripe for shorting. Citigroup for example, now there's a prime candidate.
On another note, you should also look into deep in the money put options 4 or more months out. You can make much more with much less capital, and never lose more than you put into it. I don't know why people short when put options exist, to be honest.
You can only short a stock if someone long has the shares in a margin account. Your broker can't find any such shares which have not already been shorted. I'm not sure how far and wide they look ... probably only at other margin accounts at the same institution.
The same thing happened to me with Amazon back in 2000. Dammit, I could have made a killing.
I don't hold any lulu but I'm thinking of buying in at some point soon.