http://www.safeguardcovers.com/
Yeah, whatever you do, don't go get the cheapies at say BASS Pro Shops, etc. Sergio bought one (supposedly towable) and where the scoop and headers hit it, it ripped apart like a $20 prom dress coming back from Parker..........Guaranteed, yes! and they did replace it....still....only 1 trip with it at 75MPH.
I had mine made for Pickle (An SST V-Bottom) here in town at a shop in Tempe. He double layered it where the pipes, steering wheel, seat backs and scoop hit it, rope strung clear through it's perimeter, etc. Nice stuff!

I'll check and see if he's still around doing it tomorrow, but he mostly does Bimini's. I don't ever tow with a cover on, but he still folded and triple stitched everything, set it up with D rings on all the seams so I easily could if I ever wanted to. (I hate those plastic snap lock strap deals, lemme use a bungee or a ratchet strap on it). I think he only charged me like $250 or so, and was a deal at that, VERY high quality!

Ray