Chris Adamson: I think you have that backwards. Apple's JVM has been Cocoa-based for a while now (since 1.4). SWT is Carbon-based. And even that wasn't a deal-breaker before. The real problem seems to be that:
The new JVM is 64-bit Intel-only
You can't mix 64-bit and 32-bit code in an OSX process
Carbon is 32-bit only and apparently will remain that way
SWT is Carbon-based
For what it's worth, QuickTime for Java won't work on the Mac's Java 6 for exactly the same reason. Carbon is de facto (but not de jure) deprecated, and therefore any Java libraries that use Carbon are in big trouble.
For most use cases and development, SWT seems to be one of those ideas whose time has come and gone...
I'm sure porting SWT from 32-bit Carbon to 64-bit Cocoa is something that is doable but will require some time and effort. The question is: "Is it being done?"
It seems it's time for Eclipse users to be patient, as Swing users were patient in the last ten years.