If you have a 2 wheel drive truck that can't get traction on a slippery ramp, has anyone ever tried, snow chains? plywood? carpet strips? Or anything else, that would solve the problem?

4wd.......

short of 4WD, weight in the back and a good limited-slip rear end are your only hope...

i have a locking rear, just wondering what pulling out a top gun is gonna be like.

Doubt you'd be able to use chains on someone's ramp without someone getting pretty upset. The other stuff you mentioned is worthless.

You might get away with dumping some coarse, abrasive. I've used a blasing media called black beauty- it's crushed coal cinders. If where you're at is heavy with algae, it might bail you out of a jam. An extra 1,000 lbs in the bed won't hurt. If you plan on launching 3 times a week, there's only one way- 4wd

4wd

Ltd slip

What about brake throttle modulation (this works wonders for humvees) or a front end tow rig to hook up in the front so the rear wheels are higher and on the dry pavement?

some ramps are so chitty that your hood would be underwater around here....

That and the weight of the trailer (tongue) on your front axle would reduce the down force on your rear axle trying to back you out. Your only safe bet is investing in 4WD, or having a buddy there with a tow strap.