I would tend to agree that you should try one of the big Mercier frames... I have an IRO group buy 62cm and it fits me well but it's more like a 59cm. I am 6'2" with a 34" inseam. I could take a frame another cm taller to be honest, but the bb is taller than my 59cm conversion and I can feel the height with a toe down.
So yeah. I think an IRO wouldn't be tall enough for you if you want a bike that fits well in the classic sense, as opposed to having a tall seatpost and stem combo.