I saw the Australian film "The Dish" last night. It contained a perfect example of the trailing "but" as anastrophe (or substitute for however/though if you prefer to think of it like that):

"She's a lovely girl."
"Not much of a driver, but."

This usage is certainly not a recent fad, although you wouldn't want to use this film (set in New South Wales, Australia in 1969) as a source of accurate historical information, given the poetic licence apparent at times. I can date my first experience of the "terminal but" to January 1976 - on a bushwalking trip I met a guy from New South Wales whose use of it was so chronic that we nicknamed him "But".

And you've gotta see the film if you get the chance, for these reasons, amongst others:
1. Classic example of the Australian sense of humour (he says, at the risk of being accused of rash generalization).
2. Great nostalgia trip back to the Apollo 11 mission, for those who are old enough.
3. The soundtrack (mostly pop songs from the era) ain't half bad.
I just hope it travels OK - it's a bit hard for me to judge how it will be received elsewhere.