Thank you, Razorback!
I have a silly aversion to seams. I am a seamstress which is the only possible explanation. For some reason I long to have a seam free cover on my dream foamie. Another side effect of being a seamtress is that I want to know the direction of my grainlines for strength and stability. I've noticed that tarps don't show the edges (selvedges of the cloth) so you cannot tell what is length or width. I know - picky, picky, picky...
I went and looked at Big Duck and at Dick Blick (shocking prices), then I went back to Dharma Trading so I have a lot of stuff rattling around in my head. What I am wondering about the most is fabric weight advantages/disadvantages because weight affects the cost of canvas so much. I've been enjoying the early comments on GWP's thread where the discussion goes from old bed sheets to fiberglass fabric.
I did find some 12 oz for sale on Big Duck for a great price, but it was dark brown or caramel colored. Makes me wonder how good primer is at suppressing dark cloth colors.
After having read all those old discussions and a few foamies have been on the road for a few years, I feel compelled to ask, "Has anyone tested this?"