"Luan plywood" is kind of a generic term. Most who ask about this stuff are refering to the 5.8 mm luan underlayment that the bigbox stores sell. It's not very good for the reasons already mentioned.
I have bent good quality ¼" underlayment (it wasn't luan) with a heat gun. I was making curved blades for some old Folbot paddles. But, these pieces weren't very big and the curved area was small it wasn't hard to warm the ply up sufficiently.
On most of the old designs that featured cambered decks the ply was bent cold. Of course, it was 3mm or 4mm okoume.
As far as I'm concerned the luan boatbuilding wars were fought by better men than me and prooved to be a dead end.

: Without a lecture on how okoume is better than Luan, I was wondering if
: anyone could shed some light on steam bending luan plywood for a cambered
: deck. Actually any bending method that results in a crack free luan deck
: would be great.