This should be added to pycoin and not btctxstore! APIs should be select randomly, but weighted with respect to latency. - Chromanode: [mainnet](http://v1.livenet.bitcoin.chromanode.net), [testnet](http://v1.testnet.bitcoin.chromanode.net), [docs](https://github.com/chromaway/chromanode/blob/master/docs/API_v1.md) - https://www.bitgo.com/api/ - [bitgo.com](https://www.bitgo.com/api/#blockchain-data) - And any other usefull blockchain data services
