Thanks - I read through the link but I totally missed the "Rename Partition" option.
However when I added the string to the "com.apple.Boot.plist" it doesn't work.
I'm using what I see in the Chameleon boot screen (after pressing tab) as input:
hd(0,2) OSX
hd(0,3) Linux
hd(0,5) Linux
Thus I have added the following to /Extra/com.apple.Boot.plist:
<key>Rename Partition</key>
<string>hd(0,3) Backtrack;hd(0,5) Ubuntu</string>
However when I boot it still shows Linux and Linux.
I know this is the correct plist and it is being used as changing the "timeout" parameter has an effect.
I see screenshots of Chameleon boot screens from Feb 2009 with renamed partitions so I know my version (2.0-RC3-nbi) should be OK (I believe "Hide Partition" is available as of RC4)
Any ideas?