I was able to get a i3 2100T setup to 13W (without keyboard n mouse attached), maybe the ivy bridge variant should idle a little lower (but i also read somewhere that doesnt downclock that low so take my comments with a grain of salt, research)... but its going to be hard to reach 10W, go with an Intel mobo (not as tweakable but very efficient mobos) and a very efficient PSU on low loads like PicoPSU-90-XLP
and search for very efficient bricks (on DC setups i dont have a clue). SSD be careful some are not that efficient, research some, specially on notebook forums, as some look into this more as they want to get more battery life, from what i remember i think crucial m4 was a not the best but not the worst either. Go with only 1 fan, the cpu fan, as my fans take 0.5 to 1 watt... so the less the more you will be close to your goal.
Another option is going with mobile CPU, there are CULV sandy bridge, i guess there are some ivy bridge as well, there are very few options from what i recall, JetWay JNC9B-HM67
, not sure how efficient they were, as i steer away from them as there were very few cpu coolers.
Be sure to post your finding once you finish, im interested on seeing how low you go.