Have you thought about using Varnish in front of your web servers? That would do nice static content caching. Unless the mess of code under the bonnet of Wordp

Have you thought about using Varnish in front of your web servers? That would do nice static content caching. Unless the mess of code under the bonnet of Wordpress is a concern and you want more flexibility in controlling it then I see your decision as sound. However it is hard to beat Wordpress's extensibility and ease of use for publishing content online.