Repeated thanks to all who entered clues. Repeated apologies for the delay. My opinions are below. The winner is revealed at the end.
Stout bag holder (6)
PORTER: double def
-- Absolutely solid double definition, with a vivid image.
Retire pet mongrel - it's done and dusted (9)
PRETERITE: RETIREPET anag; def = done and dusted
-- I like the anagram fodder (I especially like mongrel dogs) and the anagram indicator. The definition is just a bit too fanciful for me.
Strange fruit (5)
QUEER: double def
-- It's good to see a double definition that's also a recognisable phrase. Most definitions of 'fruit' (as meaning a male homosexual) identify it as at least derogatory, and certainly if this were a clue in a (UK or USA; Australian, I don't know) newspaper, the definition would need to be qualified with this in mind.
Altogether rum! (6,5)
PRETTY QUEER: re David, a cryptic definition
-- Can't really see this as a cryptic definition. It's simply a synonym of one word and a synonym for another. Yes, the answer obeys the criterion of the challenge, but the clue just doesn't have the cunning of an effective cryptic clue.
Duke (I include this because I think it actually works):
Metal mixture that smells bad there, after he leaves (6)
PEWTER; PEW + T(h)ER(e); def = metal mixture
-- Duke withdrew this. My initial response was that the removed H and E don't have to be contiguous; as long as they are in the same order as they are in T(h)ER(e)), that's fine. There is, however, an argument that 'leaves' implies that HE as an undivided unit should be extracted, which is not a bad argument, which is why I like cryptic crosswords so much, which is a cop-out on my part...
I'm going with Rob's bag-carrier as the winner. Second is Steve with his Billie Holiday song.