Directory listing levels with payment (premium listings)

I know many of you are interested in having different levels of listings with the user paying for premium listings. This is certainly crucial for me and something that I have spent most of my time working on. The object being that a premium member can add more details then a basic member and their listing would be placed above the basic listings.

I have tested the following modules for suitability of collecting payment from users:
1. Pay per node (part of ecommerce)
2. Paypal node (part of ecommerce)
3. LG Paypal (not part of ecomerce).

There are two main ways of approaching this:
A. One listing per user. Listing is the users profile.
B. Multiple listings per user. Listings are nodes and not part of the user profile.

I initially looked at the first way (A) using a combination of views, cck, node profile, views fusion, LM paypal and field permissions. The advantge of this approach is that it is fairly easy to upgrade from a basic to a premium listing/account using LM Paypal. This is done by changing the "role" when the user pays the fee via LM Paypal and using field premissions to make certain fields available to "premium" roles only. You can use Views Fusion to place profile/nodes from premium users above those of basic users.
The major disadvantage of this approach is that a user can only add one listing, because it is tied into the profile. So if the user works for a chain of stores, for example, he/she would need to create a new account for each store. It also makes it a lot more difficult to create listings yourself (see the thread on populating the directory), because you need to create an account first for each listing.
An important note here is that I could not actually get LG Paypal to work. It is still in "Head" status and seems to be quite buggy.

I prefer the second approach (B) because it is more flexible. The administrator can create business listings on behalf of businesses and transfer ownership of the listing(node) to them later when that business creates an account (a good way to initally populate the directory). I used Pay per node (and ecommerce) to charge users for adding premium listings.
When you create the Pay per Node product (create -> product), you specify which content type it is for. So simply create a content type for premium listings (using cck) with all of the relevant fields and set it to "sticky" so it sits on the top of the results.

The process for the user is something like this:
i. create an account
ii. Purchase the "pay per node" product via Paypal
iii. In "my account", click on "Pay per node" and then you see that you have one available node. You click on create, and add that listing (which creates a node with the content type of "premium" (or whatever you want to call it).

The major problem with this is that it seems to be impossible for the user to upgrade from a basic listing to a premium listing because they are two different content types. I have tried the "Node Type" module to enable users to upgrade by changing the content type, but this do NOT force when to pay for the node, because they are not creating a new node.
Does anyone have any ideas on how to enable users to upgrade without having to add all of the data again?