Allow customers to clone an issue from the customer portal

We are evaluating Jira Service Desk and have a service desk workflow where customers often submit the same requests again and again, but with slightly different data in the fields (e.g., changing dates, titles, etc). To date this is done by emailing in a fairly long Excel template, and our user research has indicated customers often keep around the last few Excel files they submitted to use as starting points for the next request they submit.

For JSD to have a viable UX for our use-case, we would need customers to be able to look through their "My Requests" section on the portal and clone an issue to save time on the next submission. This doesn't appear to be a feature at this time, but has interest from others as seen here: https://community.atlassian.com/t5/Jira-Service-Desk-questions/How-can-my-customers-clone-an-oft-used-issue-in-the-JSD-Customer/qaq-p/88518