My 10 cents (is that a dime?)
Quote:
At about 3200 rpm, I'm getting a pretty noticeable vibration from the engine (doesn't matter what gear).
Because you've said DOESN'T MATTER WHAT GEAR, I'll assume you have no vibration whith the engine running at 3200rpm, with the bike standing still.
I'd check the tension of your chain on a bike lift or such. Check it through full rotation - many rotations. You may have a dodgy chain - stretched at some point, even after 600 miles. A tight spot will be "felt" through the engine. It would come and go, a repetitive drone/vibration.
Any easy check if you can get the back wheel off the ground. 
