I read this article about early '90s Warner Bros Television Animation series and was surprised that the conceptual Tiny Toons version of Speedy Gonzales was turned down because the series already had a speedy character in Little Beeper.http://www.retrojunk.com/details_articles/1120/
Lightning Rodriguez was going to be the fast mouse's name and I think I may have spotted his only appearance in an early episode of Tiny Toons.
Thanks to the awesome, brand new DVD set "Tiny Toon Adventures: Season 1 Volume 1" I was able to watch a quick scene frame-by-frame. In the scene, a bunch of Tiny Toon models fly by the screen and I noticed a little mouse character who wasn't Lil' Sneezer.
Note the Chuck Jones-esque sneakers this mouse is wearing, Calamity Coyote & Little Beeper wear a pair just like them. I wish we would've seen an actually cartoon starring Lightning. Maybe an animatic will pop up on future DVD sets? Who knows?