The question is - can you politely correct someone's spelling without being thought of as a troll?
I believe the answer to that question is no. I have tried in the past and failed many times. I am a grammar nazi as well, but NO! I cant correct people's grammar!
A few days back, I suggested this feature:
https://bitcointalk.org/index.php?topic=627768.0Honestly, I think it's a great idea to implement into the new forum software.