How close are development webservers to production webservers?
Generally, they are same in terms of the settings which are required to run the applications which include the environment setting. 
However, the clients genereally have dev systems which are less powerful in terms of the processing power and other h/w resources. I have seen using them virtual servers in dev evironment since they generally have multiple projects going on in parallel an this helps them reducing the cost.
Most python frameworks will have a development webserver of some kind that will have a warning that it isn't for use as production servers.  How much different do they tend to be from their production equivalents?
I haven't quite decided which framework to go with, much less what production server to use, so it's kinda difficult for me to pin this down to a "compare development server x to production server y."  So with that said, let me make the question a little bit more precise:  In your past experience with a python framework, how much time did you have to spend getting your application up and running with a production system once its been developed on a development server?  Or did you skip the development server and develop your app on a server that's more like what you will use in production?