Second vote for an electricians knife. It sounds like you are looking for a
cable splicing knife. While somewhat out of your price range, a second option would be the
Graham Pocket Razel.
EDIT: The Boker Cop Tool is a budget version of a Razel.
As a maker of knives, and a total knife freak, I have never seen the appeal of a short blade on a long handle. Just my personal and professional opinion on the subject. But they are gaining popularity. I saw an article on them in a magazine several months back as I waited at a store.
I've found that long handle/short blades are easier to work with when you really have to use a lot or force and/or precision. Also, if you're as injury-prone as I am, it cuts down on the amount of blood you lose.