I thought it would be a better idea to make this more visible than just posting it on #74, and I've fixed one of the problems I mentioned in my posts there. I also have no idea how to submit a proper pull request (reading Github's help made me even more confused) so please forgive me for submitting this as an issue, I don't know any other way to contact the people working in here.

Link: https://www.dropbox.com/s/zts9g9vj6ndnvya/Unity%20IC2%201.7.10%20backport%20v1.1.zip?dl=0
Notes:

• Couldn't find any of these files among Unity's textures, possibly due to them having been removed from IC2 in 1.8+: itemLathingTool.png, itemTurningBlanksIRON.png, itemTurningBlanksWOOD.png, turnables/IRON, turnables/WOOD
• Couldn't find matching IC2 files for these Unity textures, possible due to them having been added to IC2 in 1.8+: iridium_reflector.png, quantum armor overlays, obscurator_mask.png, rci_lzh/rsh machines, fluid tank
• Couldn't find armor models, so there's a heavy disparity between armor icons and models
• Terraformer isn't animated because that would heavily inflate the texture size, due to how old IC2 textures worked
• blockPersonalChest.png and Unity's personal chest seem to be too different, so I didn't touch them
• Lathe textures are missing from the Unity textures (might have been cut from the mod)
• Fermenter textures aren't missing from Unity, but they're exactly the same as vanilla IC2's ones

(fixed a typo and the icon for silver ingots too)

[months late edit] I put this up on Curseforge for better visibility, in case anyone else out there cares as much as me. I'm a total novice to this sort of thing, so if there's any license-related problem, please tell me and I'll delete the project from there as soon as I can.
https://minecraft.curseforge.com/projects/unity-ic2-1-7-10-backport

[even later edit] No point in keeping this open for so long, please yell at me with messages if I shouldn't have uploaded it to Curseforge.