Excellent article.
It's true that the market for 400's has greatly diminished in recent years, which in turn makes them either a bain to have them or a god send.
For example sourcing parts can be hard, my ZXR400's downpipes have rotten and a genuine set from Kawasaki are just shy of £500 and that is for another set of quick rotting downpipes. Even some of the well known manufactuers are not producing for the 400's any more e.g Scorpion, and I think Micron.
But even so with parts awkward to source if you have a minter they are desireable to the second hand market even with high mileage and I won't have lost too much money from when I bought it, again there lies another problem where even tho I know I should get another bike due to the bike being cramped and hurts my knees due my manly size. I just can't bring myself to let it go.
I think this could be a good thing for the Journo's at TWO to look in to. Could fill a few pages.