membership plugin API reference?

The default 'Join' and 'Account' dynamic page content in membership is not as flexible as I would like. Is there an API with PHP references I could use to do things like:

- create a 'sign up for Premium access now!' button anywhere on the page
- add the user's current membership level(s), anywhere on the page
- detect the user's membership level(s), and decide what to do (e.g. 'if (membershipLevel = 'Premium') { echo "yippee!" } else { echo "nuts" }, etc)
- display a different 'No Access Message' depending on the membership level (i.e. "This content requires Premium access... click here to go Premium." vs. "This content requires Pro access... click here to go Pro.")

Many thanks!