The ability to show an upload progress bar will depend on whatever file upload library you are using. Hoop.la uses jQuery File Upload to show an upload progress bar on the standard Hoop.la UI. Since you are using a custom UI via Hoop.la templates, you will need to look at the client-side file upload library you are using to determine feasibility of displaying an upload progress bar. There's nothing on Hoop.la's server-side implementation of the file upload process that is required for a progress bar, as the file upload progress can be determined purely on the client.
If you'd like our assistance exploring the options and developing an implementation, we can offer our Professional Services time at $200/hour. Note that this team would need to be scheduled based on our availability, as well.
If you have any other questions, let us know!