OK, as someone who has been trying different methods of QoS over the past years, with varying levels of success, mainly to have my VoIP phone rock solid over DSL, I'm very interested in what you're saying.
Is there a reason this approach hasn't been implemented yet? Does it break something? If my router is lying to one my upstream router about its TCP window size, wouldn't that impact both the FTP and video stream?
I have my Kodak ESP 5250 working very well on Fedora with the CUPS driver on Sourceforge. Just unpacked the file and then installed the printer (as a network printer over wifi) using the standard Printers icon in the control panel (I think it was called CUPS Printer Configuration Utility.) Worked first time.