Try Avast. I was just poking around in the settings and found an exclusions option where it appears you are able to put in a path.
As for the rest, I tend to find it's much more productive to keep the trojans off your system in the first place. Really doesn't require too much effort on my part either. Bulk of it is really just using something other than Internet Explorer, and some other fairly common sense type things.
I`ve been using free Avira anti virus for a while. I need a feature where I can set the anti virus software NOT to scan a specific folder in my Computer; I`ve messed around with Avira and haven`t found out this feature, it keeps saying that some of video files that I have myself filmed are viruses (!!) and deletes them, too bad.
Please, does anyone have a recommendation ? Also, as far as I`ve noticed, the free Avira does not have anti-trojan capabilities, does anyone know a free package that would include this as well ?