I have a dealer who sells both Hitachio and Pioneer claiming that the '08 Hitachis are comparable to the new Kuros in picture-quality and black level, but I can find nothing written about the Hitachis. Anyone have any experiences, or even hearsay, they can share?

Apart from the marketing standpoint, black isn't one of the most important colors on the screen. But it's the one everyone homes in on though as it's difficult to do well on flat panel TVs.
Where the Pioneer really stands out is on the color accuracy, detail and image depth. These three elements of performance are further highlighted on the Elite with a really good feed. Not by much, but it's there.

You can give me panel that's as black as the base of a pot hole, but if the rest of the colors don't cut it, there's no point in my even considering it.

The Hitachi Director's Series is decent quality overall, but not in the same league as Pioneer.

Saying that, if I had a $5k HT budget, I'd spend 20% on the screen and 80% on the audio. the picture is only two dimensional and there is limited HD content being broadcast and very limited quantities of HD movies on DVD.

Audio is quite different. Makes everything much more real and takes care of your music nicely too.

I know the speakers are differently placed and that the Elites have more setting options - I'm more curious if there's any noticeable difference in picture quality.

I hear you about HT budget; this isn't for an HT - it's for a general-use TV (lots of sports, HBO, etc. ) in the family room.

When you have a BluRay feed on the two sets, then there's a real difference. Colors look more vivid and image depth is improved, but it's not a night and day difference.
I wouldn't spend the extra myself, but then being mostly an audio bloke, I would say that.