Google and TESNexus haven't led me to anything. Is there not a Morrowind utility out there with equivalent capability to TES4Edit / FO3Edit? That is, direct editing of arbitrary records in an .esp?

I'm not familiar with TES4Edit, but you might want to take a look at http://planetelderscrolls.gamespy.com/View.php?view=other.detail&id=52 and http://planetelderscrolls.gamespy.com/View.php?view=other.detail&id=53. Though I've never used TES4Edit so I'm not sure if that is what you are looking form.

Sounds like EE might be what I'm looking for.

EE can pick out a record and edit it with a low-level interface, just be careful using it on big files (it tends to corrupt them).