The next 40-bagger may be GCFB, currently trading at $2.25. Basically, it's very similar to BJRI but only with two dozen locations. Unlike BJRI, most of GCFB's restaurants are in the rustbelt states where the economy is improving rapidly. The internet reviews are similar to those received by BJs. Definitely worth a bit of DD on your part.
If GCFB had the right "formula" or business plan, they would have caught on a long time before this. Something is lacking. BJRI has been a great mover, except for these last 6 months. I don't think anything has changed fundamentally so it may be a long term buying opportunity. I really don't know what is wrong lately but it has been so great for me for so long it is hard to be objective.