A bit late into this topic (didn't notice it before), but here are my opinions on these things:
Suicide Kill: I believe that the win should go to the suicider unless the suicidee (definitely not a made-up word) somehow survives. The suicidee should know what to look out for in his opponents character and play carefully as the match progresses.
Standing Infinites: Always allow up to 250%. These can always be stopped by simply switching characters. I only allowed the "Gentleman's Rule" at my tournament because everyone was complaining about this. =/
Planking: Definitely ban it, but I'm not sure how it would be monitored. The Japanese Lege Grab Rule seems fine, but 70 ledge grabs is indeed too high of a number.