So far I've found the following:
- opentype-info.tex by Jonathan Kew
- TypeSp01.tex -- TypeSp10.tex by Stephen Moye
- t1testpage.exe by Eddie Kohler
I'm hoping that I've missed a package (or two) as well as other information. I've got >2k fonts on my development machine and I've finally concluded that I desperately need something more dependable than my memory.
opentype-info.tex is set up for XeTeX, TypeSp01-10 for TeX and t1testpage is limited to .pfb files. I'd think that the first two could be rewritten for XeLaTeX and perhaps extended with a Perl script as needed. Any other solutions could be folded in as well.
As an example of extension, the necessary successive runs of otfinfo.exe could be formatted and combined with the above. This could all be combined in a sort of grande scheme/stew so that I or anyone else for that matter could make decisions about font usage intelligently.
As I'm typing this I noticed the question about 'Generating a table of glyphs with XeTeX' which I'll take a look at for obvious reasons. An answer before I even post the question---no wonder I keep coming back to this exchange :)