Yeah that's the very first thing I did after I read your post, set a key to call up the in-game config. I totally forgot I use that all the time when playing MAME on the PC. You know, out of sight, out of mind.

I get betwen 25-30% speed w Outrun - it gets much more consistent once you pass the checkered flag at the start. Set frameskip at 4 and it's very steady and playable, give it a try (unless you're one of those types that wants things to be "just so", but I don't mind settling - hey, it's OUTRUN on my PHONE!!! 8^)

Also I'll pass on another little trick I just came up with. Since I was quickly running out of buttons to map things to (I have been playing on a GameGripper, and recently started using a Sixaxis - very sweet), I started mapping multiple keys to the same buttons! So, my "insert coin" is also my "start" is also my "pause"! It works very well, and it's kind of fun to come up with button combinations that will be efficient but not conflict with each other. Anyway, just throught I'd share!