I remember seeing on ebay a vintage denim suit that had been made on Savile Row.  It was double breasted. 

I can imagine those suits being very uncomfortable.  Wouldn't chambray be a better choice for a denim-y casual suit?  I have a couple of powder blue chambray sack jackets, but I've always wished for a full suit in a grayish shade.  Like linen but less wrinkly.

The weight of the Demin would be make or break, wouldn't it?

And I'm with the Repp - That old pale Grey Chambray is something we need more of.

Nice jacket. very similar to my 1980s Brooks Brothers number, save for patch breast pocket (which I prefer too actually)

Press have offered a chambray sack for the last couple of seasons in blue and pink. I think the shoulders on their cheaper tailored clothing have been crap for a long time so I haven't bought one, but the idea is a very sound one.

O'Connell's have recently started offering one in blue which might be worth a look: my (slight) criticism would be that the pick-stitching would be more elegant in white rather than navy.

Cassavetes wore a light blue chambray coat very well in the early scenes of Rosemary's Baby. Interesting to note the contrast in his pale clothing in the early part of the film with the darker wardrobe he sports after his diabolic conversion.