I feel your pain.
I have experienced the exact thing. restore from itunes OR iCloud has successfully restored all my settings, EXCEPT EVERY-SINGLE-MSG. lol. Nothing. Even repeated it., no luck .
It seems to be a hit or miss.
I've read people from 3GS-i5, 4s-i5, not having the issue....meanwhile, you and I are lucky enough to have experienced it. Oh and also it's not across the board. Some people only lost certain SMS which weren't in their contacts...how odd?