A 24" vanity would just have a centered sink.

You want to buy bases separate from top, is all!

Most cabinet manufactures offer left hinged or right hinged or left drawers/ right drawers versions of the sink bases. So you could have mirror images. If you are looking for a 24" sink base it will probably have only a door or just drawers not a combination.

I mentioned Bertch Cabinets in a previous thread and I know for a fact that while they are not custom you can choose door styles, wood species, finishes and configurations like right or left hinged doors. There are other cabinet manufactures that do this too. Check out cabinets at a kitchen or bath store rather than just big box or online options.

Cabinet companies make all kinds of configurations to suit all kinds of situations. However, you need 15” from the center of the drain to a wall. A 24” vanity is too small to give you that. 70” is too small for a sit down vanity area as well.