Question : Problem: how do I extend a usb 2.0 a/b cable 100 ft

how do I extend a usb 2.0 a/b cable 100 ft and keep signal strength?
many signals can be converted and transmitted over cat-5e cable,
but I can find nothing on extending the usb over 15 feet.

Answer : Problem: how do I extend a usb 2.0 a/b cable 100 ft

http://www.startech.com/product/itemlist.aspx?product_desc=usb+extender

There are many solutions for using UTP cabling.

There are some "active extenders" that integrate an amplifier.  This allows you to use your 5m USB cable plus the 5m amplified cable.

This bus-powered, so your USB port must have sufficient juice for the signal and to power the device:
http://www.startech.com/item/USB2FAAEXT15-15-Foot-5-Meter-USB-20-Active-Extension-Cable.aspx

Just curious...why not use UTP?  It's cheaper than daisy-chaining USB cables together.  100ft can cost as little as $10 if you have spools of it with the proper termination tools.  Even a patch cable of that length is fairly inexpensive...less than $25:

http://www.cyberguys.com/templates/SearchDetail.asp?productID=2641