I've created a patch! So far it's only been tested (and not even much) with 1680x1050, my laptop resolution.
What it does: It changes the effective resolution of the 1280x1024 choice to 1680x1050 (but other options are possible), by changing some of the occurrences of 1280, 1024 and related numbers inside the binary.
It also changes all interface graphics that are 1280x1024 to 1680x1050, it this point only by duplicating the centermost line a number of times. It doesn't actually widen it yet, since I don't have enough info on the SLP rle encoding yet.
It writes a new exe and a new version of interfac.drs, both with a different name. The patched exe refers to this new interfac.drs, not to the original one. You can't lose anything.
It currenly works on the gamecopyworld version of age2_x1.exe since my laptop doesn't have a cd drive, it should be trivial-ish to port it to the unpatched executable too. (Conquerers Expansion, v1.0c).
Manual: quircky so far: inside the AoE2 folder, create a folder Patch, create a folder Data in it. Copy the input.txt and exe there and run the exe (from the data folder). It doesn't say anything yet, but you'll see the files. Note that it looks for the files in ....age2x_1.exe and ..Datainput.txt so you need to follow the instructions.....
Microsoft.Net 3.5 required.
Let me know what your opinions are!
http://sites.google.com/site/aoe2wide/AoE2Wide_0.1.zip?attredirects=0&d=1