PortableRA has this! Works great actually! It's the most complete version of original RA that I've been able to find so far.
The high resolution code is based on code and research CCHyper, hifi, nyerguds, AlexB and some other people worked on. It has to most complete high resolution support and AFAIK only the WOL menu doesn't have high resolution. I spent a lot of time fixing the skirmish and LAN menu to be centered instead of sitting in the top left corner, and I made the WOL menu inaccessible. The high resolution code is based on hifi's public code which he collaborated on with CCHyper and nyerguds. I did some simple reverse engineering of AlexB's ARDA code he wrote for the high resolution sidebar, and wrote my own implementation of that (harder than it sounds, very low level). And I fixed up some other high resolution things.
There's a lot of other code from CCHyper in the patch, including mouse wheel sidebar scrolling which he wrote.
