Add custom network device icons in Mac OS X Finder?

Seems that I was very close, I just wasn't getting my machine to advertise itself properly.

I finally got it to work:

The method I used is below:

1. First, on the Mac, I created a custom bundle which I called "ComputerTypes" by copying and pasting an existing bundle such as MobileDevices.bundle or MachineTypes.bundle in the /System/Library/CoreServices/CoreTypes.bundle/Contents/Library folder.

2. I then opened Contents/Info.plist with XCode Plist Editor and edited all the details to create a custom bundle, changing the Bundle Identifier, Name, etc.

3. I removed all the existing entries in the "UTExportedTypeDeclarations" key then created a new entry per device. Each device entry has a "UTTypeConformsTo", "UTTypeDescription", "UTTypeIconFile", "UTTypeIdentifier" and "UTTagSpecification", where the "UTTagSpecification" dictorinary contains an Array in the key "com.apple.device-model-code" with all of the mDNS _device-info._tcp identifiers to accept. UTTypeIconFile refers to a icns file in the Resources folder.

4. I then saved the bundle to /System/Library/CoreServices/CoreTypes.bundle/Contents/Library folder and rebooted.

5. On the other machine, I needed to set up to advertise a _smb._tcp service as well as the _device-info._tcp TXT record, as usual except using a custom model name rather than a Mac product name.

6. After rebooting the Mac, it should appear like the picture above.

I uploaded the finished bundle to http://dl.dropbox.com/u/4140005/ComputerTypes.bundle.zip as an example.