It's been an interesting journey thus far, and more than a little eye-opening. Every day over the last week, I've built a new class for 4e that was either based on a concept from my current campaign (set in mythical Greece), or inspired by something drawn from 3.x. Most of the classes are 1st-level only, but I recently took a stab at a 3-tier spread for my "scourge" class (martial controller, uses a flail for area control).
If you follow my blog (which you probably don't), you can find the 1st-level versions of my lurker (monk), captain (warlord), and jester (bard), plus of course, the 30-level version of the scourge (rogue - technically missing a capstone feature).
These classes aren't perfect of course, but they serve as a proof-of-concept. These are "Essentials" versions of existing classes, and if you know anything about Essentials, you'll know that it's not only an effective 4.5, but that it's actually, functionally reverse-compatible with 4.0 like the Playstation and PS2.
Lurker (monk) v.01 (based on 3.5 Lurk)
Captain (warlord) v.01 (original class)
Jester (bard) v.01 (original class)
Scourge (rogue) v.01
Anyone who's interested in learning more about the components of a 4e character class, and how to build one that's not only effective at performing its role in the party, but also "harmonizing" with other classes in its role and power source, feel free to drop me a line. I've built up a lot of esoteric 4e knowledge that I'm more than happy to share.
I'll give you this one for free -- if you thought classes in 3.x were front-loaded, what you might not realize about 4e is that every class is front-loaded, and that's one of the main reasons multiclassing fails so hard. It's literally easier to make a new character class than it is to combine two existing classes.
Next on the menu: some conversions from Magic of Incarnum and some other original classes.