We use the same icon for the ThinLinc client as we use for the .tlclient files. This could be confusing for users and it would probably be better if we have a unique icon for the .tlclient files, that better encapsulates what they are.
Citrix uses a ring with two windows in it. NoMachine uses their logo with a screen icon overlaid. Microsoft's RDP client, however, does like ThinLinc and uses the same icon for the application and its connection files.