5 years ago I assisted in the development a .NET application, this app required root access and ran on a windows VPS at that time
I have a client that wants to see my application in action - so I am willing to pay someone that can install the app onto their Win server so I can demonstrate my app

this is a short term and I am willing to [pay for this hosting+time

You can probably consider getting a VPS for a short duration and thereafter cancel it out. They are pretty cheap these days and should provide you with full admin access to your server.

If you're interested, I can set you up with a Hyper-V instance. We're UK based, so I don't know if the 80-100ms latency to Canada might be a problem. We can provide you with a SQL Server database and other services as necessary; everything should be covered by our SPLA.

Drop me a PM if you have any further questions.

Though it is bad form to have any web-application that requires Administrative rights on a system. FWIW, I'm a .NET developer myself, if you like I can probably fix-up your system so that it runs under the 'normal' permissions (such as user-isolated Full Trust, or shared Partial Trust).