Yes I compiled the latest svn with -O3 and the errors with black screens that you couldn't replicate works now.
Here's a few new tests:
R-Type 3 Third Lightning
watching the attract mode the first level shown looks fine but the second and later have corrupted sprites and tiles:
Mouryou Senki Madara 2
Seems to use the same hires mode for displaying text as Seiken Densetsu 3 does, there's a small glitch at the bottom of some of the kanji letters.
Keep up the great work!