Working link
With todays machinery, it would not be that difficult to make a tool like that. I think the question is, what materials are used? You do not want to scratch or make a dent in the receiver, at the same it must be solid enough to withstand the torque needed to remove/install the barrel.
I'm thinking something like this instead;
..but I'm no gunsmith.. perhaps finding one will be the best solution when it comes to this type of work