Hi,
I have a Dell Latitude D820 and an E6500 and I installed Linux with wireless working on both. I first tried the installation method that allows you to run Linux within Windows as an application (you will recognize it because it makes an Ubuntu folder on your C:\ drive).You cannot launch Linux from within Windows with either method unless you are running the Live CD.
Anyway, my wireless worked fine on the D820 but was grayed out on the E6500 and no amount of driver manipulation could get it to work. On that same machine, when I created a separate Linux partition, and installed as a second OS, the wireless worked fine. Go figure. I am teaching a class on OSes and 20 students have the same E6500. Some created NTFS partitions, and others EXT4 partitions, with successful results. Thay ALL had the locked out wireless with the "install within Windows" method, so it wasn't an anomaly of my particular machine. I have my E6500 at work so I can't tell you at the moment which wireless chipset is in there. I thought you might have a similar situation so I thought I'd share my story.