Personally, I'm not sure how easily the cyberpunk genre's pervasive Keep-Up-With-Technology-Or-Get-Run-Over angst would carry over into Ravenloft, save perhaps in Paridon. But then, I'm one of those folks who think that
real cyberpunk literature died out, as soon as the World Wide Web convinced the reading public that computers honestly aren't scary or impressive.
If blending high-tech into a game setting without allowing it to spread is at issue, I might as well mention a solution that the Mystara writers came up with: in a pinch, the gods (or Immortals, Dark Powers, etc) could always cheat. Take high-tech hardware out of its proper context, and the devices may simply cease to operate.
In the Hollow World -- another massive construct by powerful, enigmatic entities -- there's a small enclave of elves left over from an ancient era when Mystara was dominated by high technology. Like other Hollow World races, they were brought to the planet's interior by Immortals (OD&D deity-equivalents) who like to preserve representative samples of cultures they'd been fond of, that are headed for extinction on the surface. However, the Immortals couldn't let the Blacklore elves' tech spread to any of the
other preserved societies, so they swapped out all of their machines for constructs and magical items that
look like tech, while erasing the elves' memories of how such equipment really operated. So far as the Blacklore elves know, they're still living in a high-tech society of robots and so forth, but if they take such items out of their valley, it all mysteriously "breaks down".
I'm not saying that the Dark Powers would literally have to switch a high-tech domain's machinery for constructs, or that a
little technology couldn't be allowed to spread, if DMs want to allow it. But prohibiting any technologies above a certain culture-level from functioning in lower-CL domains wouldn't be a bad idea. Certainly, there's precedent (albeit in optional rules) for magic becoming more or less effective in particular domains, so why not technology? If Vechor's an example of how radically the DPs can muck with Ravenloft's reality, they'd certainly be capable of imposing such limitations.
"Who [u]cares[/u] what the Dark Powers are? They're [i]bastards![/i] That's all I need to know of them." -- Crow