vapeboss - 3d cart does not have any mobile API's. A direct DB connection
through a WS over SSL would be required on the server...but there may be one built in. I do have limited documentation on the api WS that is built in but it does not spec out the limitations and as I said, it is incomplete.
This wouldn't be that difficult, but getting the schema for the DB and the connection would be the difficult bit here. SSL over wifi/3,4g would not be my preferred method, I would rather see an encrypted send to the WS with decryption on the WS side for the send/receive, especially if it allows ordering. Take out the ordering and I think building this to allow a user to create a wishlist or create the cart so that a secured browser could be used to place the order would be preferable.
Good idea, moderately difficulty to implement properly.