One layout, different data - 301 redirect to dynamic urls ... good/bad seo?

Hi folks! Got a dilemma here … design vs seo

Currently we have (using the left navigation…you are taken to a branch page) these were built using the same layout, with each page hardcoded with data specific to that branch. So in essence 50+ different static pages were created. While I realize that is not great design standards, we were pressed for time, with limited resources and this was the best way to get the pages up fast!

Now that we have a bit more time to expand our ability to make this less of a maintenance nightmare, I looked at pulling this data using XML. This was the best option with what I had access to.

Now the big question is (since this is a SEO forum). My static urls will now become dynamic and look something like /branchlocations.asp?id=cottonwood and if anyone goes to, i would have a 301 redirect created to have it go to /branchlocations.asp?id=cottonwood (remember we have 50+ static branch URLS redirecting to a dynamic URL)

So taking this approach we will have a one page template, and one xml file to maintain (no more maintenance nightmare updating 50+ pages, only 2 files to mess with!) but how will this affect SEO??

One thing I know it should help with is duplicate content, having 50+ pages with semi similar content format we ran into the risk of google thinking we had duplicate content….I think having the data pulled dynamically will solve this problem.

Anyone have any insight into this situation??