It worked for me. Less than a month before the last update started I had to move a site [PR5] to a new domain [trademark issues]. I redirected the pages on the old domain via 301 redirect to the new domain. The new domain had a PR5 within weeks.
How long did you leave up the 301? I've got a really long domain I'm thinking of setting up the 301 for to a itybity name.....