This is an awesome build, and pretty much the guideline for my character. The only changes I've made is precision for empower. I'm also thinking I'll drop the ESF: evo in place of epic toughness because when I started my character I did a 18 con, 16 dex, 18 int starting build. I'm having to put my lvl 16, and 20 stats into dex to make the epic archery feat as well.
I really want to have that huge hit point pool from epic toughness so those full powered reconstructs can be hitting at about half life, and putting me to full. I went with precision because I see such a huge amount of my damage coming from my xbow while levelling, maybe when I'm all levelled up I'll change it out for empower, but I love having my xbow as maxed as possible, which is while I'll take the 1 pt hit to my evo DC for the combo of epic archery, and and epic toughness.