which is a minimalistic python wsgi development server with support for code reload?
You can use paste.reloader with any wsgi-server, aside of other paste modules.

# run paste reloader
import paste.reloader as reloader
reloader.install()

# run wsgiref server
from wsgiref import simple_server
simple_server.make_server('', 8080, main_wsgi_app).serve_forever()

Is that minimalistic enough?
From what I can tell

wsgiref - no code reload
CherryPy - more than just the server
mod_wsgi - all the apache overhead
paste.httpserver - paste is a huge package with other stuff in it
flup - same as paste, too much stuff.
Spawning - never used it but seems lightweight enough.
Tornado - not really wsgi + full "framework" 
Werkzeug - runcommand

any others out there? which one you prefer?