There are mods that involve stuff like investments. You could try Blue Hotel, IIRC it has something similar after it's main quest is over.
http://www.nexusmods.com/newvegas/mods/59134/?
Bison Steve Motel and Lucky 38 casino also have systems allowing you to build up casinos, but they're not fully investment mods...
http://www.nexusmods.com/newvegas/mods/40433/?
http://www.nexusmods.com/newvegas/mods/40531/?
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