Check out: https://commando.io https://commando.io, it is essentialy the SaaS you are describing. I'd pay for your service provided it had the following improv

Check out: https://commando.io https://commando.io, it is essentialy the SaaS you are describing. I'd pay for your service provided it had the following improvement over Commando.io: VPN support. Most SSH accounts I manage do require VPN. I don't know if it would be secure/feasible for a web service.