Last week, I stumbled across a fare from YYZ to HNL (on UA) that allowed unlimited stopovers along the published routing. The fare didn't last long, but I managed to book the following itinerary before it disapeared,
for $498.76 US, including all taxes, fees, etc:

YYZ/DEN/TUS (2 night stopover)
TUS/PHX/SFO (2 night stopover)
SFO/HNL (2 night stopover)
HNL/SFO/LAS (1 night stopover)
LAS/YYZ

Total q-miles = 10,345, which will be credited to my aeroplan account.

The fare would have been lower if i had stuck to the Mon-Thurs window.

I noticed that UA has another fare (thanksgiving) with the same unlimited stopovers. Hopefully, we'll see more of this in 2002!