tedster - 3:19 pm on Jun 18, 2010 (gmt 0)
Here's the way Google looks at it. There's no value to their users if many of the results go to the same exact content - different search results should target different information, so duplicate versions get filtered out, even if they would otherwise rank.
If your re-written page is to show up again, it will need all the ranking and relevance factors required to rank for that search query. So you've got a delicate balance to maintain in your re-write. But since your URL used to rank, you do have a good chance.