Hmm I can't reproduce the problem on my 10.5.8 machine..
the output of 'otool -L' produces this for me:
Bitcoin.app/Contents/MacOS/bitcoin:
/System/Library/Frameworks/IOKit.framework/Versions/A/IOKit (compatibility version 1.0.0, current version 275.0.0)
/System/Library/Frameworks/Carbon.framework/Versions/A/Carbon (compatibility version 2.0.0, current version 152.0.0)
/System/Library/Frameworks/Cocoa.framework/Versions/A/Cocoa (compatibility version 1.0.0, current version 15.0.0)
/System/Library/Frameworks/AudioToolbox.framework/Versions/A/AudioToolbox (compatibility version 1.0.0, current version 1.0.0)
/usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 125.2.1)
/System/Library/Frameworks/OpenGL.framework/Versions/A/OpenGL (compatibility version 1.0.0, current version 1.0.0)
/System/Library/Frameworks/QuickTime.framework/Versions/A/QuickTime (compatibility version 1.0.0, current version 1756.0.0)
/System/Library/Frameworks/WebKit.framework/Versions/A/WebKit (compatibility version 1.0.0, current version 533.19.4)
/usr/lib/libiconv.2.dylib (compatibility version 7.0.0, current version 7.0.0)
/usr/lib/libstdc++.6.dylib (compatibility version 7.0.0, current version 7.9.0)
/usr/lib/libgcc_s.1.dylib (compatibility version 1.0.0, current version 103.0.0)
/usr/lib/libobjc.A.dylib (compatibility version 1.0.0, current version 227.0.0)
/System/Library/Frameworks/CoreServices.framework/Versions/A/CoreServices (compatibility version 1.0.0, current version 44.0.0)
/System/Library/Frameworks/CoreFoundation.framework/Versions/A/CoreFoundation (compatibility version 150.0.0, current version 550.42.0)
/System/Library/Frameworks/ApplicationServices.framework/Versions/A/ApplicationServices (compatibility version 1.0.0, current version 38.0.0)
/System/Library/Frameworks/Foundation.framework/Versions/C/Foundation (compatibility version 300.0.0, current version 751.42.0)
/System/Library/Frameworks/AppKit.framework/Versions/C/AppKit (compatibility version 45.0.0, current version 1038.35.0)
I think otool is from the development tools but this shows all the dependencies. All of those are standard frameworks that are part of a base install as far as I know. The graphics dependencies and other odd looking things are brought in by wx-widgets which can be built with support for those. They could probably be hacked out, but since those are part of the standard footprint on that OS, they don't add any external dependencies.
Laszlo