How to always reveal the Safari Downloads Folder despite it being on another desktop? I use different desktops as project spaces.  This generally works great and feels organized.  I can work on multiple concurrent projects and context-switch at will when I want to resume work on a different project.  However, there's one problem when it comes to the downloads folder...

If I reveal a downloaded item (using Safari's downloads button and the magnifying glass icon next to a download), and then at some point switch desktops/projects, download a new file, and do the same thing to reveal the new item's location in the Finder, the Finder gets focus, but the front-most Finder window is whatever happened to already be opened on that desktop - not the downloads folder.  If there's no Finder window already open, the desktop gets focus.  That's because the downloads folder is already open on a different desktop.  I am forced to search through my desktops to find the already-opened downloads folder and either move it to the desktop I'm working on or close it, go back, and re-open it from Safari.  I suppose I can select the downloads folder from the Finder's Window menu, but I'd rather not have to switch desktops to get to the file I want.  Ideally, the downloads button/menu in Safari would just behave as expected.

Can anyone think of a way to get Safari's downloads button to always reveal an item's location and force it to open a new finder window if the current desktop doesn't have one already (but another one does)?  Can I force Safari to always open a new Finder window to the downloads folder?  Can I create my own downloads button in the Safari toolbar that does what I want?  Is there some good folder action to automatically close the downloads folder when some clever thing happens?  Is there a way to assign JUST the downloads Finder window to all desktops?  It seems silly that this isn't already handled intuitively by Apple.
I just tried to recreate your issue, and with multiple desktops, some with already-open Finder windows, when I click Show in Finder on Safari, which is on a desktop without any Finder windows, I get the file location shown in a new Finder window on the same desktop as Safari. I tried to mess it up but I couldn't.

One thing you might want to try, is on the Dock, right click Finder, under Options choose "None" under Assign To. Both Safari and Finder had this option selected when I was retracing your steps.

Since this is a half-baked "answer", I wanted to make this into a comment however I currently lack the rep required.