Joel, That's a good idea. I backfeed, as I have only had to do it twice in 20 years.
Mark, around here the utility company would balk about a device attached to their meter, and would require permits and a new service inspection.....
Shop is on a subpanel? Why can't you treat that as one of the circuits with a conventional transfer switch?
Or are both panels (house and shop) subpanels with a small load center between them and the meter?
If so, I believe you could use something like this whole house transfer switch (link has a link to the spec sheet):
http://www.generac.com/all-products/transfer-switches/portable