[quote=233918:@Norman Palardy]Resource Hacker seems able to open a 64 bit exe and insert resources and modify the manifest
It’s also a resource compiler extractor etc[/quote]
Tried it. Unsuccessful 
I do believe it is possible to change the taskbar icon dynamically using the code discussed here :
[code]//Change both icons to the same icon handle.
SendMessage(hwnd, WM_SETICON, ICON_SMALL, hIcon);
SendMessage(hwnd, WM_SETICON, ICON_BIG, hIcon);
//This will ensure that the application icon gets changed too.
SendMessage(GetWindow(hwnd, GW_OWNER), WM_SETICON, ICON_SMALL, hIcon);
SendMessage(GetWindow(hwnd, GW_OWNER), WM_SETICON, ICON_BIG, hIcon);[/code]
That does not look out of reach of a declare. I I remember right, this kind of call is used in WFS.
I am in a hotel room with a MacBook and until I am back home I will not be able to experiment.
The idea of using a small 32 bit helper to show the icon is interesting. You will need to manage the opening and closing of that app. Also, you need to suppress the 64 bit icon. See https://forum.xojo.com/13817-creating-an-application-with-no-taskbar-icon/0