It seems, not too surprisingly, that the way things are translated between common and Orcish are predictable. Which means you can say stuff UD zombie style. So far I've found (on other sites):
CD M L M O = NO A N A L
101 101 = Zug Zug
aw = no
ss ee oo p = me lo ve u
Apparently this is against the EULA though, so it might be best not to try it.
Don't know the level of experimentation you've tried, but the regular emotes seem to come across fine. /bow seems to be a good one to show your honorable intentions to the opposite side. I've even psuedo grouped w/ a troll before, we took turns assistiing the other one in kills. Twas fun.
Another reason why I tout anarchy online as being the best MMO I have played (apart from the tear your eyes out UI and the rocket science degree required to assign attributes) you could team up with the other faction, chit chat, kill mobs... but walk too far into the wilderness with them and one of you might not come back...