Are there any online resume-building tools -- would anyone be interested in one?
I'd love to be able to dump all my past experience on a database somewhere, and have it generate various nicely formatted resumes for picking.
I'll assume instead that your primary consideration is for easily generating a specific flavor of your resume from a single source. A few years ago there was a flurry of tools that worked with an HR-XML spec that did just that. Check out this microformats page that identifies some of these formats, standard or otherwise: http://microformats.org/wiki/resume-formats