I was like you, and thought it would be a HUGE deal to have a front sight in my sight picture while using the Eotech. I went WAY out of my way and installed a three-rail gas block with a front flip sight, so I could fold it out of the way while using the Eotech.
Well, after I modified TWO of my ARs in this configuration, I realized this was pointless, because now I ALWAYS keep my sights flipped up and just "see through" the irons and focus on the reticle. The irons just ghost away in my sight picture, and don't "get in the way" at all. Basically I wasted a bunch of money and time when I should have just stayed with the stock FSB.
ETA: I like co-witnessing the sights. Just because they're co-witnessed doesn't mean you have to USE your irons. The neat thing about the Eotech is that it works anywhere in the glass, not JUST the middle. So, you can look over the irons, or just not worry about lining up your irons for quick work. I recommend trying one out before you spend all the money to fix a non-existent problem.
Here's what I've got:
and:
My two latest ARs both have stock FSBs on them, and will stay that way.