The Modern Mullet, was primarily used to describe the style which had a combination of the 'Beckham' hairstyle with more hang down the back. Now freely used to describe any other fashion mullet cropping up.
"The Australian Cricket team decided to all get Nouveau Mullets to show solidarity with modern style"
A term of reference used by the already muletted to describe people who had the audacity to grow a mullet by actually working for it rather than by patronage and inheritance.
One could argue that the only validity of the derogatory moniker is for those who have more mullet than class - but then that could be said of the more traditional mulleted.
"This here waffle house is full of nouveau mullet!"