So, really funny. Set up new machine, tried to add printer (samsung ml-1640 / splix driver). Can't add usb printers. lpinfo -v denies ever having heard of usb. Looked at other machine where that printer worked. Can't add new printer there, but existing printers work. Downgraded to cups-1.3, lpinfo -v shows that printer, adding it in web interface works. Upgrading to 1.4 keeps the printer working.
Oh dear. You should know that without the useflags we can't say anything here. :P Resolved LACKOFCONTENT... :)