This is a shameless plug but I've created a service that aims to help with a lot of the issues that OP describes such as rate limiting, JS and scaling. It's a b

This is a shameless plug but I've created a service that aims to help with a lot of the issues that OP describes such as rate limiting, JS and scaling. It's a bit like Heroku for web scraping and automation. It's still in beta but if anyone is interested then check out http://tubes.io http://tubes.io.