These are "open" projects that ISPs can join to monitor performance between networks, I would recommend joining those instead of reinventing the wheel.
I don't how much scope or interest there would be just for a raw speed test between networks though, however if enough networks really wanted it you could talk to the guys running the NL Ring (if it isn't already a feature, you could develop it there). https://ring.nlnog.net/ https://atlas.ripe.net/ I'm not sure if RIPE allow ISPs from outside Europe to join the Atlas project, if not ARIN could start one, it's been very successful here in Europe. Cheers, James.
