Would require bigish translation tables. Even the basename of the keymaps is not consistent across all keymaps in X and console.
I don't think that any translation table is needed, just copy the string from /etc/sysconfig/keymap and leave it up to the user to enter proper value. If X is used, it will work for terminals also started, only ordinary terminal will not see the config, but that's it.
Xvesa? Could you elaborate? Xvesa can't use X keymaps, and uses console keymaps automatically if loaded by the kmap boot option.
Well, I do not know Xvesa, expected to have a similar option in the config. It looks like I was wrong, sorry.