Ideas, thoughts, experience with this?
If people are actually backing out before the page has even fully loaded, I see 3 possibilities off the top of my head:
1. Page too large, a possibility you have noted.
2. People are not seeing what they hoped to see when clicking on your ad.
3. Bogus clicks, and poorly disguised ones at that.
Also are you ad messages strong enough to bring in the right guys but keep out the wrong ones?
Also jomaxx rightly asked where are you getting the 1 second figure. A 60% bounce rate is something I have seen and has been very acceptable because of the way we designed the pages.