Request Campaign REST API - Generic approach with only 1 campaign?

Hello,

We'd like to send emails using the "Request Campaign" REST API on demand, but it looks like we would have to create a new campaign for each email we want to allow sending via the API. This is is undesirable for a variety of reasons, the main being is we now have to have a 1:1 mapping of email to API enabled campaign which then has to be accessible to our programmatic logic. 

Is there a way to just pass in the email asset id and have the campaign pick/send that email from a single campaign?

We still want the email sends to be tracked under the original email, so I don't think a single email with 'Dynamic Content" works for us.

It seems like Marketo wants to make sending emails from the API the hardest operation for people to perform.