You could use multisig transactions so that you don't put your trust centrally in one third party service, for example you could trust three independent services to each hold a private key, that way 2/3 would have to be compromised at the same time in order to for something bad to happen. For more robust security you could add services and need 3/5, 6/10, etc. I'm not sure of the exact implementation details, but in theory I think that would be one solution.

> https://en.bitcoin.it/wiki/Contracts#Theory