Hmmm. Just when I had a pfSense box listed as one of my projects...
I started looking at the Qotom Q190G4 boxes (Celeron J1900), like @displaced, but that has no AES-NI support.
http://forum.kitz.co.uk/index.php/topic,19306.0.htmlHowever, it looks like the Qotom Q310G4 (Celeron 3215U) has better cooling, but is otherwise similar, and is broadly the same price.
This is what I had in mind, and was close to ordering, but it has no AES-NI support either.
Their Q330G4 (Core i3-4005U) does have AES-NI support, but it comes with a £50 premium over the similar Q310G4 model.
Using @Chrys' hint about the N3150 having AES-NI support, I can see Qotom have a Q150 model series that uses it ... but it only comes with 2 LAN ports, whereas all the ones above have 4.
I don't really have a need for 4 ports at the moment. Is anyone actively using more than 2 ports at the moment?