Ok, what you want is listgen. There are two versions. Listgen, a command-line utility by Buddabing and Listgen.net (can't recall who developed it) which is the GUI version. Listgen.net is easier to find but I prefer the former. Both will work fine. I tie various listgen selects together with a bat file to have a 1 button update when a new version of MAME comes out.
Both versions will work, they let you generate custom lists in a number of formats including Mamewah. You will need Gameplay.ini or nplayers.ini - nplayers.ini is updated more often so start there
http://nplayers.arcadebelgium.beAs for multiple "Configs" I know lots of guys are doing that. I think its with CTRLR files. I personally am not too knowledgeable there. I forgot what frontend you use but with Mamewah at least you can easily setup a separate command line format for each gamelist so it would be easy enough to add a flag to call your -ctrlr 4psim or whatever.