There's not really many out there who do mainstream arena dnb like Pendulum, and Pendulum has significantly changed their sound in the last few years (becoming more and more mainstream, and moving on from their jungle roots). You can look at related artists on Amazon and music listening sites (Last.fm, Pandora, Tastekid, maybe Grooveshark or Spotify), but it mostly links to other artists that have some electronica background, but also have crossed firmly into mainstream pop.
From what you're describing, you like melodic electronica which is easily palatable (which is why deadmau5 and Tiesto are so popular. deadmau5 might be up your alley). Just look at whatever's popular on the European charts and you might stumble across something. All the top-100 electronica guys (Chemical Brothers, Pendulum, The Crystal Method) are all converging onto the same place, with vocals, cheesy melodies, and really busy production.
The chiptune suggestions are good given your requirements.
You started narrowing things down, but just saying Pendulum is tough to focus on, since their early work is clearly inspired from the Australian dnb/jungle sound, but they've gotten really generic with their latest release. Very few dnb groups have crossed into the mainstream, and you won't like Goldie or LTJ Bukem, I can't think of any off the top of my head who have mostly left their roots and gone pop music like Pendulum. I'm not saying that Pendulum is bad, but you're looking for electronica crossover artists, and that doesn't happen too often. There's a limited market for arena dnb, and Pendulum has that cornered.
Oh, I forgot to mention, there's a lot of clear inspiration from earlier BT (ESCM, Still Life in Motion) and Way Out West (Intensify, Don't Look Now) in with how Pendulum structured the flow of their albums in their latest releases, but newcomers to electronica would probably find BT and WOW boring. The funny thing about the genre is that a lot of people (especially Americans) get into it with the mainstream and bombastic stuff, but you start to appreciate the more interesting and layered pieces once the initial rush wears off. I got into the genre through nrg and UK hard house, and I can't stand either genre anymore.
Edited by Elysian - 9/5/11 at 12:15pm