Hello there,
you have a really nice project going on and I would love to take a shot at it. I used to implement MapServer and GIS related products until 3-4 years ago - importing and reading data into and from postgis databases, generating images and zooming/paning with custom made controls. I am confident I can deliver a reliable solution, so please accept my bid below.
A project such as yours usually has 3 parts:
1. Setting up 3rd party applications and their required infrastructure - mapserver, postgreSQL, python, etc.
2. Back-bone: Importing GIS Data and generating tiles from it; making sure they display properly in your leaflet client. Includes configuring all the apps to work together and write bits of code that bridge the gaps where needed.
3. Building functions around the back-bone so you can easily update the content, regenerate tiles and whatever else is needed. This may also include developing a leaflet based application if you don't have one already.
You may not need help with all of these but I'll quote as such and please let me know what to remove. I think 60 hours should be enough for all of it (20 hours or 3 days for each part) and I can deliver by Christmas. My quote is $10 per hour, half my usual rate, since working on a GIS project again is almost all the motivation I need. Pay only at the end and only if you are happy.
I am aware that my quote is a bit over your budget but I hope you will consider it.
Thankfully
Bogdan Nita