Anyway, was searching through CL when I came across this listed on the Cleveland version...
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CONVERT YOUR EZ-UP GAZEBO/CANOPY INTO AN EXCEPTIONAL TENT! - $139
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Ok, so, I click it and come across what is ultimately an ad for a company called Standing Room Tents.
http://www.standingroomtents.com/
They sell, for $139, an add on that will convert pretty much any 10'x10' canopy shelter into either a 100 sqft or 64 sqft tent, depending on whether your 10x10 is straight or slant leg.

Goes up pretty quick. Seemingly just hooks to the center of the roof and the four corners of the canopy frame (top and bottom) of the canopy. So, maybe another minute or two beyond however long it takes you to set up your shelter normally.
Seems like a decent deal for $139 (plus the cost of the canopy). Especially for those who already have the canopy.