In response to my post on quality fonts, mbana provided a pointer to a Typophile discussion on the Tex Gyre fonts. In particular, Thomas Phinney described their quality as "wildly variable". I suppose at the time I was using "quality" to more describe whether the fonts provided all the features I would expect to need, rather than only aesthetic quality. I have to admit when I did skim the specimens that they didn't look too bad to me. He did say that the glyphs based on the original URW designs were quite good, while the Greek and Cyrillic "range from mediocre to poor to largely useless". Phinney most certainly has more experience with Cyrillic and type design than me, and arguably he probably just has a much better eye than me.
Leon recommended Junicode, which provides the most important features I discussed. I do think its stems are a bit thinner than I prefer, but it seems very well done.
In my discussion of METATYPE1 and meta-fonts, Till pointed out the existence of the meta-font Antykwa Półtawskiego. At the time I told him that I thought he was misinformed because Antykwa Toruńska seemed to have been created by tracing scanned specimens. A few days ago, Peter Backes pointed out this rather egregious error in reading comprehension on my part. Currently, only the generated Type 1 font files are available for Antykwa Półtawskiego. However, it sounds like it was prepared using a rather early version of METATYPE1 and therefore the sources could possibly be incompatible with the newer versions of METATYPE1.
Peter also noted that he has also created a font with METATYPE1 called OCEANIA. It is perhaps not as "meta" as he thinks would be ideal, but during the time I've spent working with METAFONT and METATYPE1, I've definitely found that it is often quite difficult to come up with a reasonable declarative specification of a glyph.
I've been spending time lately learning more about working with METATYPE1, mostly for my own projects, but with the eventual hope of writing some tutorials. While working on one of my running examples, I was encountering some difficulty expressing what I wanted in a reasonably declarative fashion. So I decided to see how it was done in Latin Modern.
I was dismayed to learn that Latin Modern is not a meta-font like Computer Modern. Instead the Type 1 versions of Computer Modern (which was developed by either Bluesky or Y&Y) were decompiled into MetaPost code as raw path outlines. So at that point all of the useful abstractions in Knuth's original code and specifications have been lost.
The only other major typeface developed in METATYPE1 that I know about, Antykwa Toruńska, has no source available and from the description I highly suspect that it was developed by creating raw paths that matched the scanned specimens. This got me thinking about whether there are any meta-fonts that have been developed in METATYPE1, or even whether Computer Modern might be the only full meta-font family in existence. I just skimmed through the METAFONT sources that are included in TeXLive, but didn't see anything particularly promising yet.
In any event, going back to the original issue, I have been starting to think that maybe the limitations of METATYPE1 are perhaps not worth being able to directly generate Type 1 fonts. It could be entirely possible that working in METAFONT and using something like mftrace to generate outline fonts from high-resolution bitmaps will produce results of sufficient quality. I'm hoping to do some tests to compare the two approaches this weekend.
(It is worth noting, that the comment about METATYPE1 on the mftrace page is slightly incorrect or out of date. METATYPE1 can handle overlaps, there are just complicated restrictions on how overlapping may occur. Finding clean approaches to avoid these restrictions was why I became interested in looking at the Latin Modern code to begin with.)