That dent looks worse than it is from the rust and the slight deformation in the metal from whatever hit it. After cleaning and a go-over with frame blocks, it'll look much better - ready for some silver filler. The damage isn't as terminal as some of you fellows make it sound (if anything, it's the thought of the cost that stifles restoration possibilities).

Furthermore, a talented painter could conceivably blend a top tube repaint onto that bike. Matching the patina is the main issue in this case.

-Kurt