Allow subscription mode options on checkout forms (e.g. monthly and annual options)

I have a subscription that I want to sell for 300/m or 3000/yr (a discount for paying annually.) We can currently create an offer where the customer can select from multiple payment plans. It would be extremely helpful if we had similar capability with subscriptions.

The current work around (use two separate order forms and make the customer choose beforehand which payment mode they want) is not very elegant.