Hmm,
So, who is interested in injecting their powershell process into another process to hide it? Only advantage to this is if you are not going to be there. Makes no sense to do it with the BB connected since you are going to be there but if you ever wanted to leave something behind (like the keylogger payload) but want it to be hidden well I can create a solution for you. I planned on doing it eventually when I was done optimizing the BBTPS but I can take a break from it to think of and create a template for ya'll.
It will be borrowing from the PowershellEmpire teams PSInject mo