I just got a CNB case for my LC80. Very nice, better made than the Gibson ones, but with the same features, like two neck supports and shroud. They also shut properly, unlike the standard Gibson USA ones
Mine came in brown tolex with fluffy pink interior, but they do some in black tweed too.
This SG one is an australian link:
http://esvc001232.wic020u.server-web.com/product.asp?prodid=184387
I don't seem to be able to find them in the USA, only in Australia and here in the UK. Frets, in the Tokai registry links, have them, but I don't see the SG case amongst them.
There's a TKL Epiphone SG case on eBay UK:
http://cgi.ebay.co.uk/Brand-New-Epiphone-hard-case-for-SG-Guitars_W0QQitemZ290045570788QQihZ019QQcategoryZ20830QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
The Gator one looks similar to the CNB ones. Probably made by the same folks:
http://cgi.ebay.co.uk/NEW-GATOR-GW-SG-BROWN-SG-STYLE-GUITAR-CASE-99-99_W0QQitemZ150050896456QQihZ005QQcategoryZ41409QQrdZ1QQcmdZViewItem
There's a Gibson one here:
http://cgi.ebay.co.uk/Gibson-SG-Case-Mint-Mint_W0QQitemZ280043316629QQihZ018QQcategoryZ41409QQrdZ1QQcmdZViewItem
Cheaper case, with only one neck support:
http://cgi.ebay.co.uk/SG-Style-Electric-Guitar-Case-Fits-Epiphone-New_W0QQitemZ200042193686QQihZ010QQcategoryZ33037QQrdZ1QQcmdZViewItem
Even cheaper, with one neck support:
http://cgi.ebay.co.uk/New-Electric-Guitar-Hardcase-Hard-Case-fits-SG-Styles_W0QQitemZ330028702450QQihZ014QQcategoryZ41409QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
TKL one:
http://cgi.ebay.co.uk/SG-Hard-Shell-Guitar-Case-by-TKL-Made-in-Canada_W0QQitemZ120022793811QQihZ002QQcategoryZ41409QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
Too much choice