I don't have a direct answer to your question, but below are a few ideas to consider if nobody else here has the answer you are looking for:
1) *If* in your searches you were to come across a 'salvage' truck on the internet ..with a manual trans, often they show the vin of the vehicle, which you could plug into Mopar's site, and look up the computer. Obviously those trucks are rare, so maybe proceed to #2.
2) Perhaps, call a couple part's departments and talk to a good part's guy. There 'might' be a resource, guide, or matrix they have access to, which shows various computer part number applications (since ECM part numbers tend to change with updates/yrs). You might want to call a couple dealers. If a parts guy has 3 guys waiting at the counter, ask if there's a better time to call. Or better yet, stop in to your local parts dept (or two). They might know a regional guy who could rattle off an answer ...it's a matter of finding THAT guy. Parts mgrs know other parts guys at other dealers. You just gotta find a guy willing to do a little bit of legwork for you. I've found many parts guys to be real helpful. Some aren't, but many are. It's always great to have a relationship with a small-town parts dept. You can still buy it online..just let them know you're not at that part of the project just yet. Or ask how much a reconditioned TIPM with the options you need...would be. Sometimes dealers can get real competitive. You really want to be talking to the mgr, not the pimply kid who just transitioned over from the alignment dept.
3) If you contacted the tech support dept of these internet-based shops which 'recondition' ECM's. Maybe a guy who knew his stuff, they might have a resource. If you find a support guy who would be nice enough take a few minutes to look for you.
If it was me, I would call people personally. It's a lot easier to ignore and blow off an email. When a parts guy hears the sincerity in your voice, and gets the drift you're trying to do something neat (like this swap), and have good mechanical abilities, I believe they would be much more inclined to help.