So it seems that Siren did get a little love with the new Legendary mods, which is nice. Hopefully Gear Box truly is going to fix the Cataclysm tree (hoping they don't nerf the only raid-friendly solo Siren build--or at least make them more manageable with new fixes)
yesterday, I was farming fatty bones outside of Flamerock Refuge which very rarely spawn (there are two skeleton mobs that can produce a Tubby Bones in that area where the Mr Boney Pants boss spawns at the beginning). It took hours (was doing this while watching GB/SF game), but I got 4 spawns, and each of them dropped a Legendary--Mechromancer Anarchist mod, Soldier somethingorother mod, Berserker Torch mod (all of these level 64 or 65), and a Bunny launcher.
Well, needless to say, I got pissed with the grind (it only takes about 15 seconds to run in, scan for the fatty in those 2 mobs, logout, and back in to repeat), so I just gibbed myself a Legendary Cat :\ ...it's quite nice.
At least, in the process of making the Cat mod and saving, the game seems to have erased my legendary Psycho mod and the Bunny...so I guess there's some karma. The spawn rate of those things is atrocious, but in my experience, it was 4/4 Fatties with legendary drops. :\
I've tried going after tubby scaggs in 3 Horns Valley (the spawns near Doc Mercy), but none yet. I guess I will expand that to all the skaggs by the steam pumps. Also, there are several more bone mobs just outside that gate to Flamerock and on the shoreline--often fighting golems--so that would increase the potential spawn rate and make the grind a bit less mind-numbing.
Cliffs: anyone that wants the new legendary mods, get thee to some tubby critters and lay waste.