SM, here's my idea:
Battle of Harer
The Somalis were fast to realize that the time was now not on their side any more. Counting on bad weather to keep the EtAF on the ground, on 28 November they staged their last offensive against Harer, while simultaneously attempting an advance down the road towards Alem Maya. However, by this time the first Cuban units were deployed in the area as well, together with several BM-21-batteries. They proved decisive: the Somali attack failed at great cost.
The fighting died down, with both sides digging in and scrambling to reinforce available units: even if Somalia was subsequently capable of securing some small amount of US and Egyptian support, the Soviet airbridge was continued and soon enough it was clear who was to win the race.
Despite reports about Somalis activating all their reservists, and - reportedly - also contracting 20 Pakistani pilots and some other foreign and domestic personnel to bring the SAC back into fighting condition, in late 1977 and early 1978 their air force actually cased operations over the Ogaden. This enabled the EtAF to unleash its full fighting capability against Somali troops inside Ethiopia.
On 8 January 1978, after a series of air strikes by F-5As, MiG-21s, and MiG-23BNs against Somali positions and also the air base at Hargeisa, an Ethiopian division - bolstered by Cuban armor and led by Soviet General Petrov - approached Somali positions around Harer. These were first put under constant artillery- and air-bombardments, and then stormed by 120 T-54 and T-62 tanks. The Somali defeat at Harer was complete: according to unconfirmed contemporary reports, one of their brigades was completely destroyed, losing possibly up to 3.000 men killed in that battle alone.
With the loss of Harer, the whole Somali position in Ogaden was actually outflanked: the Somalis were forced to retreat to Jijiga and Dible, the last important crossroads in the area, or else risk being cut off from their major supply bases. The rest of Ogaden had only very poor road communications: the remaining Somali and WSLF units were scattered and heavily depending on supply lines running from Hargheisa. Once these came under a direct threat they began a withdrawal towards the border. This withdrawal swiftly turned into a rout, with Cubans and Ethiopians racing to reach the Somali border before the remnants of three Somali brigades could do so.
Recognizing the threat of such a force for other local countries, Western powers scrambled to move their units into this part of the world, and the situation became so tense that the French deployed their aircraft carrier Clemanceau off the coast of Djibouti, in order to be in position to repel any eventual attack on their colony.
I tried pulling the map up on Yahoo and google, but I don't get lat/long info which is what you need.
I'd make the theater just big enough to capture Gode to the south and what's on this map. And, in fact, I'd clip Gode and just use this map if we think it might keep the campaign map small enough. I say this because I think the best reason for creating a new theater
is to test out some of these ideas we've been experimenting with on a smaller scale.
There probably aren't more than 50 objectives on that whole map. There are 4 or 5 main axes of advance. Only a couple of major cities and airfields. We can build the theater from the ground up to only encompass these few things, add a bunch of ground and air forces based on the OOB at that link I posted, then see what happens when the campaign engine has a smaller amount of data to digest.
Hopefully the campaign would be fun, but more than that, it would give us additional insights into what the campaign engine is doing.
Before tackling something like ODS (or Nevada, which technically is very large), it would be nice to have a small sandbox to play in to test out these ideas we're exploring. Smaller means less terrain to fix, less roads to fix, less objectives to confuse the campaign engine, less units to place, and so on.
Anyway, this is just an idea, and it's sort of out of the scope of your original question about T-Rex's campaign. I don't want to hijack, but I've been sitting on this idea since last year, and since you brought it up...
I don't mind if you want to take it down, or I can help figure out how to move forward if you want. I'd been planning on using the ODS tiles for it, so now that ODS is more developed (or Israel tiles, too) that might work.