When reading this NG, I see much doubt regarding what users believe WiFi CAN do. In order to give readers an idea of what can be done using WiFi, a person could Google for WiFi community networks, and get a wealth of data regarding what IS currently being done.
Thirty mile links in Sonoma county......Seattle to Portland links......etc.
click on map to get info on the Seattle to Tacoma data!
http://www.seattlewireless.net/
http://www.seattlewireless.net/index.cgi/LongShots
http://www.dailywireless.org/modules.php?name=News&file=article&sid=946
http://www.piercedesigns.com/tacomanode/mtbaldi.htm
Surely if one understands that miles of links are possible, then troubleshooting the link from the first floor to the second should be no obstacle!