Could you run 'xinput test 7' and tell me what axis 2-5 are for? It gives me that :
me@ubuntu:~# xinput test 7 motion a[0]=4225 a[1]=2898 a[2]=0 a[3]=0 a[4]=0 a[5]=0 (...) When I "touch" the tablet with the stylus : button press 1 a[0]=7803 a[1]=4348 a[2]=53 a[3]=0 a[4]=0 a[5]=0 then : button release 1 a[0]=7794 a[1]=4350 a[2]=0 a[3]=0 a[4]=0 a[5]=0 So 2 is the pressure. But for 3 to 5 : always 0. I've saw that : http://linuxwacom.sourceforge.net/index.php/faq "Note, tilt is only supported with protocol V tablets, which include Intuos series and Cintiq 21UX to date (Nov. 9, 2006). Any other tablets don't have tilt no matter you have the tilt option in your xorg.conf or not." So maybe my tablet can't handle tilt... (I've put the tilt option in the xorg.conf) (It's the "graphire 4", A6, bought for 90 euros end 2006)
I 'd like someone to please verify this for me by sshing into their Mac OSX box from their linux box and running /Applications/Gimp.app/Contents/Resources/bin/gimp-2.4 ... you should notice that it doesn't like your tablet. If you could test Inkscape in this manor as well, I'd appreciate it... I don't use the "Gimp.app" but the "macports" gimp. And I've no linux box to test (I use linux on the mac) maybe with VMWare Fusion it can work. I'll try, I've Fedora 9 64bits installed.
I'm happy that tablet support will come in GIMP & Inkscape, it's the "main" problem for me with "nix" programs on OSX !