Is that 2 ft including the tail? Anyway, just scale them down from a dire rat to get about 6-7 lb.
Tactics: Jarbos are unassuming, gentle creatures whose first instinct is to run and hide rather than fight. Sadly for them, this makes jarbos common meals for desert predators.
Let's see... they're similar in build and size to a big Potoroid (a "Rat-Kangaroo") like a Long-Nosed Potoroo, which is about 2 feet long (including 7 to 10 inches of tail) and weight 1.5 to 4.5 pounds.
"A typical jarbo is 2 feet long (including 9 inches of tail) and weighs 2 to 4 pounds."?