I modified the poll based on discussion. Please note that you are able to change your vote if you wish. The biggest additions are the slingshot (see the concept art) and the concept of having no siege unit. I'm of the personal opinion that the latter, while an interesting concept, doesn't work so hot due to the heavy emphasis on attack and armour types. While the Nomad's have a number of fire based attacks, making them more effective versus wooden buildings, they lack an attack type effective against metal or stone buildings, which could be problematic. We can't just raise their attack strengths, either, as that would make them too strong against infantry and cavalry without significantly changing the damage to structures. Long story short, we'd benefit more from adding a new unit with an impact or anti-structure attack.
The rock slingshot proposed by MightyMic is an interesting concept. Similar to the impact ballista idea but unique enough to set it apart from other factions.