"I dunno. I've always thought that properly polished and engraved skeletons would be rather elegant servants."
Sure! Don't forget, smelly, nasty rotting zombies and walking corpses aren't necessarily any more pleasing to be around for a Necromancer than any other fellow. Morticians and coroners may work with dead bodies all day long, but that doesn't mean they want to spend all their free time around them either!
"Rotting zombie" type undead would normally be left that way for one of two reasons -- either because it's not worth it to bother cleaning them up (leaving them to guard some remote tomb? Who cares about appearances?), or because you want them to retain a more fearsome appearance (and let's face it, a shambling skeleton with rotting strips of flesh connected to it's crusted bones is scarier and more intimidating that one that's been carefully cleaned and polsihed).
If undead are used anywhere where they will be consistently interacting with either regular people or delicate machinery, you can bet they'll be cleaned up and or well-preserved.
This thread reminds me of one of my favorite 2nd ed. PCs -- he was a necromancer who took considerable pride in his craft. Each skeleton was carefully and lovingly cleaned, stained, lacquered and polished before being animated, their bodies adorned with fine brass fittings.
Of course, there's also the soulmech necromancer that I'm going to be playing soon, who animated his own corpse to serve him.
Steve M