Magento Limited Preorder Acces

Magento Limited Preorder Acces
*magento limited pre order access*

I have a few things which i am unable to achive myself on a clients magento site.

Basically the client wants a system where for the first month you can only use the site if your invited. Acess is granted by a individual code which can be emailed out to there already following market. Upon acces the users can pre order items and will not not be charge until the dispatch date.

I am using the latest version of magento with sage pay as the merchant.

The other problem would be i have a very limited deadline.

So a quick response would be great.