Slightly off-topic, but in the same ballpark - I just got around to applying cheat.txt to my .149 installation so that I could overclock Double Dragon finally.  What do you guys think of using auto savestates per-ROM to ensure settings are retained?  I understand most, if not all settings are stored when a savestate is created, and it seems to be the only way I can retain the overclock settings.  I  crafted a good configuration for my Double Dragon ROM, and loading the savestate brings back all the tweaks that didn't apply by themselves.  I bet Alpha17x's attract mode setting would also be stored if a savestate were to be created.  Worth a shot anyway.   Saving/loading the savestate works great for my purposes, but seems a bit cumbersome to have to load the state every time that ROM is loaded.  Maybe there is a way to make certain ROMs automatically load a specified state?  
I think it would be kind of cool, and a nice way to work around the issue of cheats and sliders not being saved upon exit.  I read a mameworld.info thread that addressed this, and while it is one of the most requested MAME features, the devs aren't in a rush to implement it, as it would apparently be a large undertaking.