Registration settings per product display

I would like a new feature: registration settings on a per product display basis in addition to the current per product basis.

Use case:

When using Commerce Registration for sport event registration, you will usually have a per-event product display, say "My running event" and a fair amount of registration classes ("Mens marathon", "Mens half marathon", "Kids 10 - 15 years half marathon" etc. etc.). The registration classes will be the individual commerce products that you can register for.

Usually a lot of the registration settings are shared across the registration classes:

• Total capacity for the event
• Scheduling
• Reminder

I would suggest to add a fieldset "Shared registration settings" at the top of the Manage Registrations > Settings page (node/%node/registrations/settings) when there is more than one referenced product. This will make it possible to set say the closing date for all events referenced by the product display in one field, rather than having to set it on each product.

I will be happy to code it - as a sub module or as a patch to the current dev version (should that be the 3.x version then?). If it is a sub module I might need a couple of hooks added to the commerce registration module.

Any suggestions to if this would be a good way to handle tings? And would it make best sense to handle it through a sub module (I think this is a question to jpontani).