I believe this is the most painful bug ever encountered in Mac OS X. It sure should be small, even Apple can't find it 😉
Anyway, I have found a workaround to this.
This method has it's perks such as if the pointer changes the shape, you will also still have the standard shaped mouse.... but if this doesn't bother you, or if, like me, bothers you to a much lesser extent then _suddenly_not_having_a_mouse_pointer_at_all here it goes.
1. Go ahead and download the mouse pointer I've created http://i.imgur.com/2y0ga.png and save it as MouseLocator.png in your Pictures folder (root) (Of course you can create your own png but be sure it overlapses correctly over the original one otherwise it would look weird)
2. Download MouseLocator 1.1 from here : http://www.2point5fish.com/download.html
3. Activate Mouse Locator from System Pref -> Mouse Locator and check "Always On"
4. Be free until Apple aknowledges this "very tiny" bug and fix it.
Cheers!