I caught a link from daemonnews today about Apple's forthcoming AppleScript Studio. Read between the lines, and it's just Interface Builder with new bindings.
Interestingly, one of the foundations of NeXTSTEP was having a dynamic language to handle the GUI bits. The original one was Objective-C[*], but I'm pretty sure it's been ported to Java. If the glue exists to link what's become of IB and AppleScript, can support for all-Perl apps for OSX be that far off?
*: Rumor has it that Brad Cox got to the fledgling NeXT Computer in the very early days, when C++ was barely out of Bell Labs. Had C++ been more mature, a lot of things might be very different today...