This thread is becoming more and more interesting as it goes on!
I haven't actually read the ISO standard defining the Portable Document Format, but JCFF's suggestion above regarding attachments is extremely interesting, and one I will be investigating for my own projects.
As a sometime perpetrator of under-competent typesetting, I've been faced with a quandary which I will describe as the Microsoft dilemma: I know this stuff I've been working on for years still has lots and lots of bugs in it, and might not work properly when someone comes to use it, so should I hold onto it privately until I've fixed all of the numerous problems, or should I just dump it out into the world and let everyone else deal with it?
I won't be drawn on making invidious comments about other people's typesets, so I'll confine myself to my own projects. In the main, there isn't a lot of money going around to pay typesetters to do either competent type-setting, or competent proof-reading. As a result some of my own typesets have been largely to please myself, and if anyone else happens to find them useful, that's a bonus.
The Mozart Great Mass in C is perhaps the most notorious of my editions in this respect. Back in 2001 there was a request from someone on the (very lengthy) CPDL request list who wanted the vocal score of the Kyrie from that great work. So having a long interest in the piece anyway, and having the Dover volume of six of the Mass ordinaries, I went about typesetting just the VS of that movement in order to fill the request. But then... that short Gloria movement that follows immediately afterward (and quotes Handel's Hallelujah chorus) was equally deserving of being given a typeset... so I gave in... and the next year I performed the work with the Melbourne Philharmonic, so it seemed like a good time to do MIDI or Scorch versions of all of the choral movements... and so on...
... and eight years later, the typeset consists of 200+ pages of full score, about 100 pages of vocal score, and over 500 pages of orchestral parts for 24 different instruments – slightly more than Mozart's scribes needed to generate, since they used natural horns and trumpets in a variety of crooks, whereas I have made concessions to the normative brass keys in common use.
In the meantime, while that typeset was gradually being assembled, the Microsoft dilemma I described above could be re-couched in the following terms: even if not all of the work happened to be available, was there any use in making available whatever excerpts of the Mozart were ready to hand at the time – possibly with mistakes, and with a decided lack of proofreaders – with the intention of going back and finishing off the job later? Certainly in terms of the users of CPDL, the answer to that was a thundering "yes".
I think the most embarrassing and incompetent error that went undetected for a strikingly long period of time (from the original release of the score in March 2002 through three subsequent revisions until May 2005!), was in the very first movement to be attempted, where the final notes of the soprano soloist omitted the grace notes before the end of the long cadential trill. However, it is a startling fact that in all that time, during which I received numerous e-mails regarding the typeset, no one observed that those two little notes were missing... Hmm...
On the other hand, my scores for Tallis' 40-part motet Spem in alium are one of the finest things I've done, and at Perlnerd's prompting I will be uploading my scores here shortly, in effect mirroring the set over at Choral Public Domain Library.
I am well aware of the vagaries of traditional typesetting as well as the specific rules that govern musical typesetting, and have at times experimented with my own custom house style: although I am heartily sick of reading scores where the main text font is Times New Roman, many of my scores have gone down that particular path of least resistance, just because the font is so damn ubiquitous when the score is to be distributed and printed on virtually any type of laser printer you can point a stick at, which one would hope will always have that font stored permanently in memory.
It's a little bit embarrassing when you go to the effort of finding a nice serif font like Bembo, or Goudy Old Style, or something a little out of the ordinary, and go to the trouble of managing ligatures, proper quotation marks, em-dashes and the like, only to find that when Jo Bloggs from Idontknowhereistan sent the PDF to his laser printer, the text came out like:
Cruci?xus, by Antonio Lotti (øÞ.1667?1740) instead of
Cruci?xus, by Antonio Lotti (ca.1667–1740), and the noteheads have all turned from the proper music font into something looking like: ? ? ?
Anyway, I've just been called to bed by my long-suffering partner, so I must say adieu for tonight.