[Tile-serving] Benchmarking tile serving networks

[maps at lima-labs.com]

Good morning Tile Serving list,
I've been lurking/reading for some times as I've built my own tile 
serving network. I've come to the point where I have a question that I 
think is best asked of the community than solved in house.

Does anyone have recommendation on third party providers that can 
benchmark uptime/tile serving time etc? Ideally some service that could 
pull a random tile from my CDN from different points and send me SMS 
alerts if response times were high etc..

Thanks,
Sam