A mini-HOWTO test the XKB config without modifying the system configuration.
(Only tested with XFree86 4.3+.) 

First see what your configuration is. Note the model and layout.
   $ setxkbmap -print

Then unpack the sources locally ...
   $ gzip -dc xkeyboard-config*.tar.gz | tar -tf -
... and change to the delivered directory
   $ cd xkeyboard-config-<version>

Then try to load the current keyboard using the local rules
   $ setxkbmap -v 10 -I$PWD -rules base

Now try to set different keyboards using the -model and -layout.
   $ setxkbmap -v 10 -I$PWD -rules base -model pc102 -layout intl
Look in the file rules/base for other example models and layouts

If there was a problem, you can reset the keyboard like so:
   $ setxkbmap -rules xfree86 -model <noted model> -layout <noted layout>

If that doesn't work, you may have to log out and log back in.