A musician asks: which way should I go in Drupal 5.0?

I'm a musician and I'd like to pursue a couple of different potential business models for my web site, subscription and pay-per-track:

For songs I'd like the following:

• All songs must have a preview accessible to all, which is a shortened clip from the full track... doing this automatically would be nice but I'd be fine with making the clips myself.
• The ability to purchase the song for $1 via PayPal (or some other system)

• The ability to download any song if the user has a paid subscription to the site (this should be possible via a combination of one or the other of the paypal subscription modules, and some PHP to detect if the user has the proper role)
• The ability to mark some songs as free downloads so that anyone can download them without a subscription or paying via PayPal
• Other information about the track, credits, lyrics, etc.
• I'd like to manage all songs in more or less the same way (i.e., it would be nice if free songs were the same node type as a paid song)
• I'd like a way for download links to only be valid for a certain period of time, so that someone can't paste a location into an IM session and use my bandwidth to copy my stuff (they'll at least have to send thier own). What would be even nicer would be realtime marking the MP3 with a ID with metadata for the user who downloaded it, so I could politely remind anyone sharing my stuff on filesharing networks that I'm a small musician and it's my livelihood.

For groups of songs:

• I'd like to be able to group them together into logical units using the taxonomy system (i.e., give people the ability to find songs by the CD they were released on, or if they're incomplete "beta" tracks, or just look for the free ones)
• And I'd like to display these groupings in ways that make sense (for a CD grouping I want to show the cover of the CD).

So it looks like I have 3 problems:

1. There's no out of the box solution in Drupal for accomplishing this, though many of the parts seem like they're almost there.
2. I want to use Drupal 5.0, I don't want to feel like I'm building a site which will be obsoleted in a couple of months. I know a lot of the media related modules aren't fleshed out yet, but I'm willing to put in the elbow grease to make it work with the much cleaner experience 5.0 provides.
3. There's more than one way I could peruse my goals, each with advantages and disadvantages. Since I'm not as versed as others in Drupal I'm sure there are many more that aren't coming to mind that may be very evident to the rest of you. In fact, heck, someone may have cracked this nut entirely using off-the-shelf parts, which is why I'm asking before starting work.

So here are my observations and questions so far:

1. It looks like the module CCK Field Permissions can accomplish my goal of allowing paypal subscribed users to see the download link for all nodes of a CCK type... however it doesn't look like I can set permissions of what a user can see on an individual node. Is this correct?
2. I wonder if Computed Field or Dript may do some of what CCK Field Permissions doesn't address...?
3. Is it possible to use audio.module as a field in CCK? I don't seem to see a way to. This would seem ideal.
4. I could just do my own uploading of files and use plain text fields for the locations of the files, and then use content templates to build the links.

Comments? Suggestions? Thanks!