Well, I took the alternator off, and it appears that the leak is coming from the intake manifold attaching to the head in the front passenger bank. So intake manifold gasket? Ok.

I've googled it, and looked in the aftermarket forums here with no such luck.
ARE there any options for intake manifolds that would be an improvement over stock while I've got it off? Or am I stuck with stock and call it good?
I did read that it appears to be better to stick with Ford gaskets, so I do plan on doing that.

I'm going to go ahead and replace the water pump while I have it apart too.

 

No one ever made a high-po intake for the V10. If it were me, I'd take a die-grinder to any sharp edges I find, but that's worth, what, 1/4HP?

 

Graphic I've read here but cannot say from personal experience there is a difference in head and intake gaskets, one for brand-new as-manufactured and another for service or replacement only, not reconditioning the mating surfaces. This in theory seems plausible so it might be worth a bit of investigating to see if there's any merit.

I looked for the thread this was first raised but can't seem to remember when, where or by whom it was first posted---sorry!