Despite searching all over the 'net for a tool like this, the closest I could find was Aptana, which is Eclipse based and thus painfully slow and bloated (and kinda contradicts the whole idea of browser based GUIs, doesn't it ?). Why didn't I find this before ? Why didn't this pop to the top of my many Google searches ? Arrgh ! I've been splashing about with YUI, Ext, jQuery, Dojo, et al. for months now, crafting stuff by hand, and here was this wonderful solution that I've never heard of just sitting there.
Guess I need to get out of the house more often. But that won't happen for awhile, cuz I'll be wired into TIBCOGI like Neo into the Matrix.
PS. Also liked InfoWorld's choice of NetBeans over Eclipse. I used to think it was just me, but they've confirmed my suspicions: Eclipse's huge collection of plugins is killing it. I've had people recommend Eclipse as a solution for simple data analysis/BI tools...and then I'd stop and think about the BI users/analysts I've known over the last 15+ years. Very smart people, but if you dropped Eclipse in front of them, you'd lose a lot of friends and associates very quickly. And help make MSFT a bigger pile of cash on Excel licenses.