the XL dosen't sit above any other way of stating 'large sizes' The fact remains someone goes to a local costume shop and accepts what fits - same as everyday shopping - Sure oversized clothing in general will allways have a nice niche particularly in catalogue sales.
'XLdressinggowns' are probably sold 1,000 fold more than fancy dress hire etc but, But even that term is still over defined for any on-line money making market.
No value