vordmeister - 6:40 pm on Jul 3, 2011 (gmt 0)
I was asked to report back on the results.
I made the move at the end of April. All pages were 301 redirected to their equivalents on the new site. No changes in content or structure with the move. Everything worked!
There was no drop in traffic for the shop section even for a day. Sadly there was no amazing increase either, but that takes time to build and I reckon a separate domain is a better starting point.