There are other lightweights worth considering:
Sanitaire SC9050 DuraLite Lightweight Commercial Vacuum Cleaner at 10 pounds.
For what it's worth, Dyson does offer a lightweight vacuum as well. The performance was middling in Consumer Reports, but I mention it because they tend to have fairly positive user reviews.
Although canister vacuums tend to weigh more overall, I'm not sure that they wouldn't be a better option for someone wanting a lightweight vacuum. Certainly with some you feel like you're dragging along a dead pig. However, most of the time, you're just pushing the power nozzle with the canister parked. My mother in law who's in her 70's uses a 20+ year old Rainbow. While it would be heavy to carry everything at once full of water, in practice you don't. The canister rolls, and you only push the powerhead and the hose. Dragging along the canister might be a drag, but in general it sits while you move the power nozzle.
Totally forgot about the 9050.....ive yet to run across one....and havent heard anything on how it performs. wonder if its durability is on par with its comm. red line big brothers tho? Anybody have a chance to test or use one yet?
turtle1