It's such shame that the Mongol Empire is not in the game, it bothers the heck out of me every time I am researching horse back riding.   The Mongol Empire is a perfect fit for the game.  

Leader: Genghis Khan

I can't wait to see the art work of Genghis Khan from you guys.   I would be so amazing, and oh please offer us the option to buy wallpapers of the game.  

Starting Tech: Horse Back Riding (Dahh) 

The Mongols start with a Great General. 

Starting with 2 scouts instead of one, and only require half productions needed to produce a mounted unit. 

Combat Bonuses: +1

Starts with Feudalism.

I certainly would like to see the Mongols along with the British and French - maybe in an 'Empires' expansion. I like the idea of the Mongols starting with a great general, but not with the other bonuses you mentioned - thats far too much and no need for the extra  +1 combat bonus with half price feudal cavalry.

Any news or work being done on another expansion?

I'd like to see some new ideas on the Economic victory condition as so far in the games ive played it has been the poor relation. Maybe when Great Britain are introduced we'll see this. Great Britain: Leader: Queen Elizabeth I, Starting tech: Sailing, Govt: Monarchy plus some bonuses on trade and economics - eg start with a coin and gain a coin per new city built and a start tile with a good few hammers and water for harbours.

Some fans made those civ (homemade). Playable and really enjoyable (no arabia like that are a bit overpowered). Even 3 new techs. Now we play with 25 civ. 

The next expansion would almost definitely have these civs:

Aztecs
English
French
Japanese
Mongols
Zulus

These are the remaining six civs in Civilization: Revolution, the specific game off of which this board game appears to be based.

In any case, I am in the middle of a project to re-design the official civs and add in the six new ones, and I'm nearly done. But it might be a little while before they're available for download, for various reasons that I don't want to get into.

http://boardgamegeek.com/filepage/76950/new-civilizations-sioux-babylonian-maya-zulu-vikin

http://boardgamegeek.com/filepage/72919/new-civilizations-aztec-english-french-inca-mongol

http://boardgamegeek.com/article/8645264#8645264

http://boardgamegeek.com/thread/918095/new-civ-and-new-tech-ufaq

There you can find the new civs created and 3 new technologies. They are all homemade and very enjoyable. Well balanced. We have more fun playing with and choosing it random. There is also the uFAQ i've made about all issues that can occur due to new abilities.