I will most likely be there as Izaya so long as it doesn't coincide with anything too uber important (like guest signings or concerts or something). At the very least I'll try to make it for a portion in able to get some pictures.
I love Durarara bunches, and last year's gathering was pretty cool in terms of how many DRRR cosplayers attended.
Just curious, how long do you plan on having the gathering go on? 30 minutes? An hour? Till everyone leaves?