What I'd really love to see is this concept provided as a service by all of the big streaming/gaming/large-content-blob providers and aggregated into a single page.
I have absolutely no reason to believe that every well-known "speed test" app/site/utility out there isn't being gamed by my ISP. A speed test that showed me my actual streaming bandwidth from Netflix, actual download speed of an XX MB file from Steam, actual upload bandwidth to some photo-sharing service, and actual latency to XBox Live or some well-trafficked gaming service would be awesome.
There is good reasons for this, it can help a ton in figuring out where exactly the issue is. If the speedtest server is off-net, you have no idea where the problem lies. Transit provider? Peering? End network? my wifi? Last mile?
I'm not sure this would need to be managed by any of those companies though, I think everything you listed could be tested in a browser by a 3rd party. May require authorization to those services though.
I have absolutely no reason to believe that every well-known "speed test" app/site/utility out there isn't being gamed by my ISP. A speed test that showed me my actual streaming bandwidth from Netflix, actual download speed of an XX MB file from Steam, actual upload bandwidth to some photo-sharing service, and actual latency to XBox Live or some well-trafficked gaming service would be awesome.