[ffcmike]

One possible solution Ben Rain has suggested on RC is to use a combination of the 2.
This would involve a normal Clientside HD running, aswell as additional serverside hitboxes to hit those who are lagging so significantly that they remain lagspiked on the same coordinate for a certain amount of time, for example when the hitbox is first dropped, and something like 0.5 - 1 second(s) afterwards.

I wasn't too fond of the idea at first,
but it just might work.
It would mean that it becomes possible to be hit from what would appear to be long distances again,
but only if and when you hit a spike which would normally mean you are impossible to hit with entirely Clientside detection, anybody with either a fast or slow/delayed but reliable connection would not be affected by this.