Sounds like you have quite the project!
For design sensibility, I always find that tables are still a go-to for two things: forms and email newsletters. I’m sure some others on here will disagree with me, but forms (especially dynamically generated) look best with a grid-like, common structure. And I think it makes them more user friendly. Just try to keep all your CSS in the linked files though – adding inline styling via table elements is a recipe for design frustration down the line.
Just my opinion – anyone else have a good solution?