HD update on a 16'x9' theater advice

Located in our barn (yes this sounds odd but it works out amazing) we have built a home theater for movies and sporting events. It is 16'x9' in size and is a custom paint mixture that i found on this site (which apparently is now deleted). I've been using a 480p projector with a 1080i HD feed from time warner cable. The projector is a hitachi edpj32 http://www.projectorcentral.com/Hitachi-EDPJ32.htm

With an HD feed this has put out a really nice picture and i am pretty happy. However, i now have more money and am debating on upgrading the 480p projector to either a 720p or a 1080p. Is there any specific things i should be looking for since im throwing the picture so far? The room is light controlled and can be brought to almost total darkness in the middle of the day so that is not an issue. Any suggestions from people who have much more experience than me in the projector world.

I will post a couple pictures of the setup tonight when i get home.

I wrote this without knowing the throw distance (i know bad idea) I will be measuring this tonight. I am thinking i wont be able to afford 1080p and i have been looking at 720p projectors around the $1000 mark. I'm not sure if the picture quality improvement will be worth the cost.

I currently have lcd. I probably wont get a dlp because i have a tendancy to see rainbows.