nope. I've been looing for a way myself. I even went as far as changing the cursor textures inside the game, and it ends up truncating my image to the smaller size anyway.
As far as losing the cursor, some people suggest right-clicking so the menu pops up and shows you where your cursor is, or use the Windows hot-key thing that puts a recticle around the cursor at the press of a certain button.
I have my game set at maximum resolution, 1600 x 1200, roughly off the top of my head. The mouse cursor is very small at this resolutions and easy to lose in the onscreen frenzy of battle. Is there a command line parameter or something to increase cursor size. There is nothing in Options, and Control Panel cursor size has no affect on in-game cursor size.