Hi Dominick, I second Richard's question about your underlying assumptions (why is XML a goal in and of itself?). That said, if you're committed to structured authoring and want a reasonably inexpensive solution, I'd strongly recommend that you take a look at DocFrame from Scriptorium (Sarah O'Keefe's company). It's as close to an off-the-shelf structured solution as you're likely going to find.
It sounds like you're going through the same decision-making process I went through a couple months ago. We narrowed our choices down to Arbortext, home-brew structured Frame, DocFrame, and (just for kicks) unstructured Frame. What surprised us is that our requirements lined up better with unstructured Frame, so that's what we ended up going with, but DocFrame was an extremely close second. Definitely worth a careful look. In terms of transitions from unstructured Frame to structured solution X, my understanding is that it entirely depends on the "implied structure" that exists in your current, unstructured files. If you've tagged your content consistently, using a template that defines formats based on their content rather than intended appearance, mapping the unstructured content to a structured solution (such as DocBook or DocFrame) should be reasonably straightforward. But if your content includes a lot of "cowboy formatting" and non-semantic application of formats, you may have to clean up the source content before any kind of transition can take place. Depending on the longevity of the existing content, it may be more cost-effective to create all your new content in structured solution X and phase out use of unstructured Frame as the need for the existing content wanes. Good luck! Andrew Becraft Senior Technical Writer Singlestep Technologies P: 206.838.7982 E: andrewb at singlestep.com