Very impressive! You didn't get all of the Mauritania territory (the western bit of the North African coastline) so that's another area you didn't get to. But this does demonstrate the challenge isn't completely impossible. (By the way, I set that pretty b&w map of Trajan's territory as my desktop wallpaper.

)
I would propose that we add another facet to our challenge:
The Roman Empire was very well-developed as far as infrastructure. Simply conquering all that territory is not such an enormous big deal, but developing it a little while you do it may well be. I propose the following:
(1) Roma and four other cities must be size 5 or more with Barracks and 100 or more culture.
(2) All cities above size 5 must have Aqueduct.
(3) Roma and at least two other cities must have Collosseum.
Is this agreeable? I don't think it's realistic to have a roman empire comprised of a string of undeveloped little cities.
So the requirements for completion can be as follows:
Code:
1: Territory - borders must believably encompass at least 90% of the Roman Empire as of Trajan's rule ([URL="http://www.socialstudiesforkids.com/graphics/romanempiremaplarge.jpg"]map[/URL]), not entirely excluding any province or area (noteworthy extremities: England, Iberia, Dacia, Armenia, Mesopotamia, Mauritania)
2a: Infrastructure I - All cities under Roman control must be connected to the Roman trade network
2b: Infrastructure II - All cities above size 5 must have Aqueduct
3a: Culture and Establishment I - Roma and at least four other cities must be above size 4, have Barracks, and have 100 culture or more
3b: Culture and Establishment II - Roma and at least two other cities must have Collosseum
4: TIMING - At a chosen point between AD 50 and AD 200, all above requirements must have already been accomplished