Rod-N-Bobb's manufactures floats for several species of fishing. There are 2 float models that would work great for crappie and panfish.

http://www.rod-n-bobbs.com/index.php?page=home

The Boss float has a stainless steel spring wrapped stem, which acts as a shock absorber. When the fish swims off with the bait, the stem will be pulled down through the float, which acts as a platform. The fish will feel less resistance and there is less chance of the fish spitting out the bait. The resistance on the float increases as the fish pulls more. The maximum resistance is reached when the fish has pulled almost the entire length of the stem through the float.

See how the Boss float works

http://www.rod-n-bobbs.com/index.php?page=prodList&by=line&by_id=TheBoss

Then click on the link 'Check out The Boss Bobber in Action'

The Duz-It-All float can be used as a fixed float or a slip float.   

http://www.rod-n-bobbs.com/index.php?page=prodList&by=line&by_id=DuzItAll

It looks like the Rod-N-Bobb's floats can only be purchased in the U.S. I have never seen them in any of the tackle shops I have visited in the GTA.