Super telephotos lenses are designed to replace (supplement) all the lenses you have in your arsenal. There are a few that are available including Canon's 18-200mm, Nikon's 18-200mm, Tamron's 18-270mm, and Sigma 18-250mm.
I understand that to get such wide focal range the image quality won't be as good, the lens will be slower, and there will be lens creep. However, is it still something that I should look into getting anyway to replace my current lens lineup when I want to travel light?
Normally, when I travel, I would carry my Canon 10-22mm f/3.5 -4.5 USM, Canon 24-105mm f/4L IS USM, Canon 70-200mm f/4L IS USM, and sometimes even my Canon 50mm f/1.4 (for low light). Needless to say, it's a lot of weight lugging around all these gears.
I've been debating for some time whether a super telephoto is a worthwhile investment, and I'm still hesitant in purchasing one. I spent so much money on the lenses that I got that it seems silly to replace them with a super telephoto.