@michaelcahill Do you have an opinion about what the best solution for this is?
I could:
 * Add new ```__wt_metadata_xxx``` methods that take ```WT_ITEM``` key/values.
 * Replace the current ```const char *``` key/values with ```WT_ITEM``` 
 * Make a copy of the values in these WT_ITEM and pass them into the existing API.

None of the options are particularly appealing to me..