I still haven't sent the 7D off - I suddenly got a ton of requests for shoots, and I'm not comfortable doing them with my XTI at this stage.
They also asked for RAW copies of the corrupt files, and I didn't have any (I deleted them, they were no use to me) - so I've been waiting for it to happen again - last night during a self portrait shoot, I got one. This time I did some playing - Aperture and file copies both bomb when they come across this bad file. OSX renders the thumbnail and preview for the file correctly - but once opened in Preview (the app) or any editor (Aperture or Picasa tested) the corruption shows through.
I'll send it in after this next big shoot, I think ... hope the turn around time is quick!