Whether it's worth it or not would depend on your career plans and interest in the topic.
The curriculum Computer Engineering is (very, very roughly) Computer Science + exposure to EE. Obviously they try to work in topics that amount to specific applications of CS/EE to engineering of computing devices/systems. My first step for evaluating this would be to figure out a list of exactly what courses you'd need to add in order to do this, and see how many of those interest you enough to both give up a year's salary as an engineer, another year of late nights and ramen, and in general making your remaining time as an undergraduate significantly tougher. Dual majoring means course scheduling can be even more "interesting" than usual, and you're highly likely to end up taking more demanding courses at the same time than usual since you're circumventing the work they do planning the degree program to balance it such that they keep from burning out otherwise promising students. Dual majoring in two tech/science majors, this is very likely the case.
I don't think as a general rule that dual majoring makes you significantly more employable. It may give you a background in interesting combinations of topics, or a better depth of understanding of a topic, which *can* make you more employable. It really depends on your career goals and personal interest in the added topics. Just don't decide to do this lightly.