This tool Referencer seems to do everything that I have until now done with bibteXML. Screenshot below for coolness. Referencer allows you to tag files on your machine rather than build up a deep directory structure.
Image stolen from Davyd Madeley’s blog.
[...] When I saw Aidans post about Referencer i was intrigued by the GNOMEy interface. It’s really usable but it’s a bit restrictive in editing the BibTeX fields. For example, I like to keep article abstracts and comments in the BibTeX entry so the I can search more accurately for key terms. Referencer doesn’t make it easy (they appear as one long line in the “Extra Keys” list) since it’s not a common practice. JabRef allows this and even if there was something else I wanted to store in the BibTex that JabRef doesn’t cater for, I could edit the raw BibTeX and it will remain untouched by JabRef. [...]