I got one last fall from an online place called Carolina Carports. I paid about $1300 for a 20X20 cover, installed. I already had a concrete pad. It has worked out well for me. Got two of my cars out of the weather pretty much. I did have an issue with the installers decision on how to place it on my pad. I wasn't there at the time...but the company at least compensated for my issue with a small discount. Very nice product.
We don't have a snow problem here so, can't address that. I will say that it is quite sturdy in my opinion. Also, I haven't talked to them about it but I'm pretty sure that you could close it in later if you want.
http://www.carportcentral.com/caroli...pxoaAjSx8P8HAQ