I’ve just discovered @awesomerobot’s awesome Discourse Category Sidebars add-on!
Unfortunately I don’t have time to modify it myself as I am meant to be launching a new forum on Monday 
Here’s what I need as a mvp (some of this is already possible):
- The Sidebar to appear across the whole desktop site (currently only possible on certain pages)
- The ability to specify a default topic for the sidebar (so shows for every page that does not specifically have a sidebar topic set)
- The ability to specify a topic for each section of the site that overrides the default topic, mainly: Latest, Categories (and all categories - already possible), Tag (and then the same topic in the sidebar for all tags - though it would be nice to make this play nicely with Discourse Tag Sidebars), Top, Users, Topic (and then the same associated sidebar topic in all topics) /u and Search. (Currently only some pages are supported)
- Each page view across Discourse requests a fresh version of the associated sidebar topic OR (and better still) it checks to see whether the associated sidebar topic has changed, and if it has, displays the latest version. (Currently it only picks up the changes after a hard refresh)
There are also some other things I’d like to see added in future too, but the above is the minimum I need in order to use it.
When do you need it done?
ASAP 
What is your budget, in $ USD that you can offer for this task?
I’m not sure, since most of the work is already done, how does $100 sound?
I’m also happy to donate the amount to a charity of your choice if you prefer 