multiselect text in Drupal 5

I see that this issue has come up before once or twice but I haven't seen an solution:

I'm maintaining a D5 site where users are asked to select countries from a long multiselect list. It's a plain text field, not node reference and also not associated with the location module. Errors are common because it's cumbersome for users to ctrl-click from a 200+ item list. Some need to select all or many countries, others only one or two.

It's clear that the D5 version of Multiselect only supports nodes. Have long multiselect lists for text fields been addressed in Drupal 5? Is there another common way of handling multiple country selection? Thanks for any suggestions.