I'd also wish NO TECH TRADING could be integrated as soon as possible, since for many of us I'd think that's important for multiplayer (and for me in single player as well).
Yes, that would be great. In the meantime, while browsing the XML files I found that there's an XML attribute to tech named "AICannotTrade".
I do not know whether the AI will honor this flag, and I have in no way tested this, but here are two mods that are beta 5.2 copies of the techdefs with this flag set on every single technology:
AICannotTrade beta 5.2 (fixed)
AICannotTrade beta 5.2 (not fixed)
Two versions, because one is a straight copy of the official tech files (not fixed) and the other is a straight copy of the TechFiles my BugFix-Mod uses (those are the original 5.2 files with a few bugs removed).
Again, just to make sure:
I did not verify these mods. I just patched these quickly together after reading your post. So why not try out whether this works properly? (Only applies to new games, not for saves)