Hey VideoNoob,
If I'm getting you on this, it sounds like you want to resize the overall dimensions of the video according to the image contained in the video. (Note that these are two items that are very often different in dimension and aspect ratio!)
I have found that DVDFab is by far the easiest-to-use converter with the best resizing and cropping options out there, maybe you need video-editing software! :D
Here's one more suggestion: try defining a 2.35:1 proportioned screen resolution as your target video size, then use the crop function to cut the video down to the image boundaries.
ONE THING ABOUT THOSE BARS...
No matter what you do, unless you have a "super-widescreen" 2.35:1 monitor, you will always see letterboxing (black bars) with images of that proportion. Getting that long skinny rectanglar image to fit on even a regular 16:9 "widescreen" monitor will produce letterboxing.
Have a look at this Wikipedia article for more info on letterboxing:
Cheers, and hey if it aint broken, keep foolin' around with it! :o
Organdude