If you are game for the smoking jacket and cap theme for the Saturday at the Dragon then my advice is to search for dressing gowns on Ebay rather than smoking jackets. It would appear that smoking jackets are doing a brisk trade (I know I can't believe it either) whereas there are plenty of eqaully lurid dressing gowns fetching much less.
You can buy new smoking caps on Ebay for £15, but I reckon a short stint at the sewing machine will be enough to knock up an acceptable copy, complete with curtain tie-back tassle.
Cheers
GC