£70,000? really? It might be too heavy as well lol. I just get really impressed with these massive white lenses you see at football matches and think they really look the business. I like the idea of sitting on a roof somewhere in a city with one and taking lots of zoomed in candid shots of people etc..
You could do it cheaper - join the special anti-terrorism branch of any police force or the secret service!
I would like a Canon f4.0 500mm but don't have 5K lying around . . .