Hi Harry,
That might be possible with some JavaScript, but I am not sure what it might look like. You may also be able to set up a custom validation rule on the Contact object itself as an alternative.
I wonder though if you could set up a duplicate check in the Skuid page itself. Before trying to save the contact info, query another Contact-based model for any contacts that match the contact’s name. That way, you can keep Salesforce’s built-in error behavior intact, but intervene before it gets triggered. I’m not sure what you want to do with any discovered duplicates, but there would be a lot of possibilities with the actions framework & models.
