You can use Javascript on the templates to re-create the picklist on the fly without having to touch the existing forms.
If you have a good Javascript developer available, you can have a custom solution implemented that meets your needs.
I like to have some JS files linked from all (or most) of the pages that I manage (over 3,000 right now) so that I can apply global updates as needed while minimizing the effort.
For example, if your country options need to change you can replace them upon page load with a new list using Javascript. Jquery is my method of choice to do those kinds of things.
Sample:
$jQ("#FieldName").append('<option value="'+YOURVALUESARRAY[1]+'">'+YOURVALUESARRAY[0]+'</option>');
In order for this to work, there is more code needed,
but any good Javascript developer will be able to create the logic you may need.
If you have the resources, that is probably your best option.
I have my default list included in a "variables" Javascript file.
I keep my funcions in a separate JS file, and can override the values at the page level if necessary.
Good luck!
Rafael