g1smd - 8:47 pm on Mar 22, 2012 (gmt 0)
This is an interesting idea. I don't remember seeing it before.
I first mentioned this technique in 2003 and have used it several times since, the last being a couple of years ago. This happens when moving a site from a free host to paid hosting.
I initially worried that the old site might be seen as being a series of doorway pages. However each page of the old site links to multiple pages of the new site, not to a single page, and the content is similar if not identical. I usually added a notice along the top of all the old pages stating that the site had moved. In many cases I also added the meta robots noindex tag to the old pages after a few months. A year or two later the old sites were taken down.