Silver spoon much good sir? What you will not find is a simple drop in .deb file. You want this, you're going to have to do a lot of the work on your own because 1990 is not calling out to any of us - nobody beyond an exceedingly small number of people want something so minimalistic.
If you don't want any gradients, patterns, or eyecandy, then just delete the transitions and uninstall all your themes, that way you'll be left with bog standard ugly GTK in all its light boring goodness.