Where are you located? In the Northeast, Heroic Racing Apparel makes a damn fine custom suit. http://www.heroicracing.com His suits are a little old-fashioned and heavy as hell, but Barnacle Bill makes a damn sturdy suit http://racingleather.com Those would be my two top picks. Fwiw, in 6'8" & 245. My next suit will be a Heroic.
I have been looking at Barnacle Bills suits but haven't heard of Heroic. I'll check them out. Thanks!
Heroic is a small company based out of Long Island, they've been supporting STT here in the eastern division for a few years. I'm having a custom suit made, here's one of the initial designs:
I just picked up a set of Teknic Chicane 2 piece in size 62/52 and I am 6'4 and 275lbs. They are a little snug but fit. I got a screaming deal on them as they are the old pattern.
Sportbike Track Gear sells custom pilot suits. http://stores.sportbiketrackgear.com/Detail.bok?no=8619 As for big off the rack suits Alpinestars is really good with a lot of their larger sizes.