I'm not aware of 27hpi gauze available for sale anywhere - although it's possible it might have been available at one time and someone may have old stock. I fully agree that silk gauze will make a much nicer carpet than mono canvas - it's thinner, and will look much more to scale.

An important point you will need to think about is that silk gauze is not woven exactly square - therefore your carpet won't be square unless you fudge the number of stitches. On a carpet that large it will be much more noticable than with a small cushion.

I don't know what sort of design you are planning to do, but perhaps you could use the 30 ct and add some background around the edges to make it the exact size you need - just a thought.

Missy