Check out this video:
at the end the guy does pushups with his feet in the air !!
how the hell can i learn to do that ?
amazing core strength obviously...
That's just a planche push up. Coach Sommer has an article on planche and level progressions. Do a search and you should be able to find it. They are fun and you'll be suprised how fast your strength goes up.
Yeah, that's a wicked, wicked video. I thought it was fake for a long time. Turns out he's for real.
I'd second the planche pushups and add some sort of gymnastic routine for all around balance and strength.
Wow; how many times is this video going to be circulated here.
Anyway... I have no help to offer, but the day you can replicate that guy, post it here with your training regime. It will be refreshing, inspiring and, best of all, new.