*rubs hands together* Boy are you in for it....
http://www.amazingmagnets.com
http://www.engconcepts.net/
http://www.wondermagnet.com
The last one also has ferro-fluid.
Also, in response to to one pole of a magnet being "stronger" than another... If a magnet is symmetrical on a plane perpendicular to the poles, then they're the same strength. You can increase the surface gauss at one end by tapering it to a point, however. It doesn't matter if this end is a N or S pole, however.
For lots of info on magnets and stuff, see:
http://www.dansdata.com/magnets.htm
http://www.dansdata.com/magnets2.htm