I didn't know which forum (Turbo or PC Engine) to put this in since it is not region specific, but the question still remains, and people seem to frequent this room more.
Are there any games to run in the 512x240 resolution mode? Do any games use it just for a title screen maybe? I know R-Type runs at something like 352x240 but that is the highest I've seen the Turbo go. Most games run at 256x224, I believe.