People being eager to try TEI and there being no official place to post TEI files, everybody has posted the files they have marked up in a different place. I have been working on my dialect, Jeroen on his and DP is cooking up another one. There is no central "clearing house" where we can see the other guys work. I don't say it would be impossible for me to obtain a glimpse of the TEI texts the folks at DP are working on, it would just be much easier if I could get them from the archive.
Personally, I try to stick as closely to TEILite as possible. I can add extentions to it, but then can easily produce XSLT to pull out those extentions before posting. I think a few of Marcello's extentions for PGTEI are not needed, as elements exists to encode the same information, or alternative mechanisms can be divised within TEILite -- but even if you stick to pure TEILite, you will need to agree on conventions, for example, I leave in quotation marks (as I have numerous old works that deal with these in a very irregular way, turning them to <q> and </q> would be difficult. Marcello leaves them out. We can fix an XSLT to re-supply them, and even an XSLT to supply them only if they are removed (given we agree on a standard way of documenting this fact) -- and that is what you need if you're working on a certain project using TEI -- a gentle intruduction and some guidelines. A few very nice ones are on the Net. If people wish, I can set up a website with TEI versions of _all_ my posted texts, both in my original master SGML, and converted to XML. Gives everybody something to experiment with. Jeroen.