Do you know of a Rabbi who rejects modern technology?

I don't believe so.

I'm aware of those who view change as something suspect; and who are afraid of opening a can of worms of applying modern science to rules of thumb that had worked otherwise. (For instance, the Talmud seems to say that certain kinds of fish are kosher because their parasitic worms do X, and now the scientists are saying that parasitic worms do Y.) There was one hyper-traditionalist Hungarian rabbi who felt that Chinese food was dangerous because it was newfangled and nontraditional! Very few follow his opinion, put mildly. Many have opposed the Internet, but not because it was technological per se -- out of concerns of what it could do.

So anytime new technology comes along, it's reasonable to ask, "how does Jewish law and philosophy view this?", and "is it wise for us to adopt this with arms wide open?" But that doesn't mean ban it outright.

I have heard that there are some Hassidic individuals who drive cars, use cell phones, and the like; but will only wear a mechanical pocketwatch, not a quartz wristwatch, as they prefer that their personal dress follow tradition. But that's rare.

Lastly, sometimes modern technology + Judaism = better modern technology. Your grandmother's oven could have been safely left on for a 48-hour Jewish holiday; then in the 1990s they added automatic 12-hour shutoffs and all sorts of bells, whistles, and indicator lights that kept Jews from being able to use their ovens on Jewish holidays. In response, Rabbi Moshe Heinemann of Baltimore (a man who was frequently spotted tinkering with his car engine in between Talmud classes) worked with engineers at the appliance companies to add in programming for a "Sabbath mode" -- you enter the right key combination, and suddenly the oven is programmed to behave like a 1950s model.