Can anyone tell me where to find the Rogue Stone needed to get into the house in the bridge district?

Thanks

When you finish the Trademeet quest the guildmistress will give you one as part of your reward. That's just one of many available in the game. I think I've gotten at least 4 or 5 now. That place is one tough battle and depending on the level of your group, you may want to wait awhile to try it.
Trust me on this!!!!!

My main character's a monk at level 14 now, so I have some pretty heavy duty magic resistance and the "quivering palm" which works wonders. That guy alone is a one man wrecking force now, plus with Yoshimo's traps will it still be that difficult? I've heard it's possibly the toughest battle in the entire game... ?

This is also just a side note, but i've defeated Kangaxx and the Red Dragon, and despite Kangaxx being the tougher of the two to beat, the game still says that the Red Dragon was the harder enemy (experience wise, I guess). I just find that kinda strange