Using the same logic as for my idea of renting a wifi with password, we could have a site help us rent a computer with a specific operating system and/or software, and paying in bitcoins directly to the owner of the machine.
According to the licenses of them it could be legal or illegal to rent specific machines.
This could use something like TeamViewer - that is what I use for remote access. It works great with all sorts of devices.
But the website would actually help you find a specific machine and use a specific client (that could be other than TeamViewer) for the remote access according to your criteria of choice.
It doesn't seem overcomplicated to develop such a website.
I think I am going to try to implement such, using PHP, for hotspots and remote access for strangers. 
It would certainly be another jump into disruptive matters.
What do you reckon?