Yeah, I found out after I wrote the README that SingIT doesn't write SYLT lyrics.
If I'm understanding your second point there, I think you're saying that lrc2sylt just converts one format to another. That's not correct. I think I tried to mention in the README that lrc2sylt reads in LRC files and writes SYLT lyric frames *to the MP3 file.* So no "mind melding" of the SYLT tag into the MP3 is necessary -- id3lib takes care of that.
The thing is, it's just a command-line util, we'd all love something prettier. Oliver PM'ed me saying he's going to cut his teeth on a GUI-based tool to do the job, but he plans on using .NET technology to do it, so I'm afraid that won't help a Linux snob like yourself. That is, unless one of these .NET frameworks like Ximian or dotGNU actually work, which I doubt...
Anyway, the ideal situation for me would be having both WinAMP 2.x and XMMS plugins to do the job. I see myself focusing on emphatic development for now, so any kind of taggers/plugins/GUI's are going to have to be someone else's bag. I can get into those in the future, but I see emphatic doing other things in addition to just the lyrics, and I wanna develop that stuff first. That, and I'm woefully behind on grad school projects.
Anyway, just wanted to clear up the fact that lrc2sylt does indeed write tags to the MP3.