Sure you can get the glass only and you can also fix it yourself. However, two things. If you get the glass, you run the risk of it not working properly as Dave has verified. If you search around the internet you can find those that have recorded the "taking apart of the Evo" and they clearly state that it is VERY difficult to get the glass back in properly because of the gasket. Yeah, Dave said that too.
You can pay 100 dollars for the glass or 150 for the entire assembly. Next thing...why would you pay 100 or more for the glass/assembly and not just take it to a shop and let people that do this type of repair for a living do it for you???? It cost me 45 bucks to have a "professional" perform the repair and I couldn't be happier.