You can just extend the existing one, no need to replace it. You can usually get a length of hose cut to length or buy a packaged length from your local auto store. Just measure the inside and outside diameter of the breather hose so you get the right size extension. Then just buy an adapter to mate the two together.
I think I extended mine 4", at the axle.
98 Sahara, hp44/hp60, warn 5x5.5 premium hub conversion, 4.88, arb's, hydro assist, RE 4.5 SF /w 3.5 springs, Novak / Teraflex SS SYE, currie anti-rock, JKS 1.25" BL, 36" bias iroks, PSC Tube fenders /w 3" flare, PSC Ricochet Rockers, custom rear bumper, btf front bumper / winch plate, warn 9.5ti, full cage, TwistedStitch seats, RCI-2161a fuel cell