Jens,
You're right that distance is a critical factor in the actual speed of throughput. I don't agree with your numbers though. I use high speed symmetrical DSL modems to extend my LAN off premise. I have achieved sustained throughtput between 1 and 6 mbps in the field depending on distance and line quality. The specs on the modems claim 10 mbps but even in the test lab we could not exceed 7.
_________________________
Give a man a fish and he will be back for more. Slap him with a fish and he will go away forever.