While it could be done, since there are numerous trainers available that are far easier to acquire, there isn't much point.
If you want a mod to spice up COH:OP, I recommend my Ewiger Krieg 5-19-2008
LinkThat latest edition adds full unit expansion for the Allies and Wehrmacht, so that now all four factions can 'cross access' the units from their brother faction.
For instance, when playing as the Wehrmacht you could also build all the Panzer Elite goodies and vice versa, while playing as the Allies you can access all of the British Commonwealth units and vice versa. On top of that, many units you're not really supposed to have complete access to like the King Tiger, Jagdpanther, Hummel, Priest, M26 Pershing, and especially the Camo-Panther are now unlocked for direct building and without limits on population!
With over 3,000 downloads of the original version, the latest version is well over two times as involved and all the better for it now.
[Edited by knightpress, 5/23/2008 8:51:04 AM]