There seems to be one major point of incompatibility between SCP and non-SCP FS2 data, and that's non-SCP builds crashing when they encounter a SCP-specific flag (such as 'no pierce shields' for beam weapons). Providing it's not too much hassle, could someone maybe put add in an optional escape character for the parser when it encounters a comment?
That way, the old FS2 will see ;new flag and disregard it, but SCP builds would see the escape character and realise the following text should be parsed. It's a simple idea but I don't know how much modification to the parser code you'd need to make. This would negate the need to have SCP and non-SCP friendly mods, I believe. Do-able?
Sid.