Well, the first time I heard it, I thought it was my radiator fan bearing. It's not.

The noise was very short lived the first time, and was almost in synch with the fan cutting on and off, hence why that was my first suspect. However tonight, I got to hear it a good bit longer and identify it.

The sound appears to be upper engine, coming from the rear bank. It's in sequence with the engine, but only under load conditions, IE accelerating. during idle it either drops off completely or is almost inaudible.

It doesn't sound right for a tapping lifter, though I know the car is burning oil somewhere (still working on finding it) so it is possible, could it be a bad PCV valve perhaps? Or is there something known in that area to cause that issue?

Could be your evaporation purge valve, commonly noisy on a 380 and it's in the right area.
Plenty of threads/posts on here about it.
Very easy to replace, new costs around $100 from a dealer, used around $65.
But if you get a used one no guarantee it won't be just as noisy.
Easiest way to check is to unplug the electrical connector and see if the noise goes away.

Okay, and where would I find such a beast? I'm guessing on the rear bank, and by the name used for it that it's much like a PCV and on the rocker cover, yes yes?

It's behind and attached to the upper inlet manifold, slightly to the passenger side of centre.
Look for a black rubber tube running from the charcoal canister towards the driver's side.
When it's running you can feel this tube pulsing.

Have a look at the first post in this thread, it has pics showing what you are looking for:
http://www.aussiemagna.com/forums/showthread.php?t=93441&page=1

Awesome, thanks for the link TreeAdey! I'll be getting that knocked out asap.

Well, the valve has been replaced, and the constant tick is gone.

However, I now have noticed that one of my lifters is tapping when the engine is cold. Once it's warmed up to full operating temp, it goes away.

Joy of joys, once I have the money, I get to tear the heads off and replace the lifters now. Though, I was planning on doing the timing belt soon anyways, so it's just going to be a two-day job instead of one.

So, does anyone know where I can get the lifters from, or am I going to have to go to the dealership to acquire them?

Well, the valve has been replaced, and the constant tick is gone.

However, I now have noticed that one of my lifters is tapping when the engine is cold. Once it's warmed up to full operating temp, it goes away.

Joy of joys, once I have the money, I get to tear the heads off and replace the lifters now. Though, I was planning on doing the timing belt soon anyways, so it's just going to be a two-day job instead of one.

So, does anyone know where I can get the lifters from, or am I going to have to go to the dealership to acquire them?

Lifters can get noisy, but most people leave them alone - depends on how bad it is, really.
Heads don't need to come off if you are doing lifters.
But first I'd try the engine flush/oil change routine.
If no joy, just replace the one noisy lifter, replace all with new ones and you are bound to get one that leaks down quickly. lol
You could always pull all of them out, and go through the clean/test/prime routine.

A noisy lifter can sometimes be caused by air trapped in the cavity, preventing it from getting enough oil. There is a workshop manual procedure for 'bleeding' this air out, going my memory it's something like "warm motor up then idle for 10 seconds, raise revs to 3,000 and keep there for 15 seconds, idle for 10 seconds, 3,000 revs for 15 seconds, idle again for 10 seconds, repeat this cycle at least 10 times, then let idle for 2 minutes." But as I said, I'm only going by memory, at least part of this is probably incorrect, best to check the workshop manual.
I tried this procedure years ago in one of my attempts to cure a mystery 'tick' my motor developed at around 30,000 k, but it didn't work, and nothing I tried ever worked. Different weight engine oils, various oil and fuel additives, pretty much everything other than renewing the lifters.
I posted an image of the workshop manual page in one of the "380 ticking noise" threads, but I couldn't find it just now, feel free to search yourself!
Worth a try I reckon, you never know it might just work for you and save you heaps of time, money & effort.

Wynns oil system flush, leave idling at least 20 mins, new Penrite HPR 10 or 15, wynns lifter treatment

IF it is the lifters should fix this. If only when cold start may be the pre tensioner

I seriously hope it's not the timing belt pre-tensioner, I don't have the money for that right now.

I'll try the Wynn's stuff as soon as I am able, though I've never had much luck with anything similar in the US when one of the lifters on my GTO went to crap.