Still working on this, but from what I gather there seems to be something horribly wrong with how Webkit renders CSS3 TTF typefaces on OS X when placed on top of a Web GL canvas. Don’t currently have the time to make an investigative demo, but perhaps it will help someone else on the far reaches of the internet to know that they are not alone.
Used Cinder this time instead of Processing. Extensive use of VBOs means that this version runs almost realtime (Tel Aviv really pushes my poor graphics card to its limit — Paris and Rome run at full speed no problem). Tel Aviv gets really busy at :16 / 8am