727-200's with Raisbeck Stage 3 kit are using flap mods and other wing mods to meet Stage 3 requirements, without engine mods. AA is modifying some to meet standards until enough new 737-800's arrive. I think TWA is modifying 727's the same way, although DC9's are using engine mods.
A worrisome threat is airports banning hush kitted planes, and only allowing Stage 3 planes to land, this being proposed for Burbank airport, and by the European Union. The hush kits that bring jets into compliance with requirements should be allowed to use airports where the market exists.