700R4 pan on 4l60E?
http://www.transmissioncenter.net/PanShapes.htm
Keep in mind that if you are going with a deeper pan, you will need a deeper (truck) filter. Also, deeper pans and pans with cooling fins are in more danger of damage, especially if your car is lowered or there are a lot of speed bumps etc. in the area's you drive. May want to consider a good transmission cooler first, although deep pans do have other benefits.
Just my $0.02


And I agree, an easier drain is always a good thing! 