baldly written function

egalize.clj

(defn pad [n coll val]
  (take n (concat coll (repeat val))))
  
(defn egalize-colls [coll1 coll2 pad-item]
 (if (= (count coll2) (count coll1))
   [coll1 coll2]
   (let [smallest-coll (if (< (count coll1) (count coll2)) coll1 coll2)
         pad-count     (if (= coll1 smallest-coll) (count coll2) (count coll1))]
     (if (= coll1 smallest-coll)
       [(vec (pad pad-count coll1 pad-item)) coll2]
       [coll1 (vec (pad pad-count coll2 pad-item))]))))

Disclaimer: I know it's written poorly. It would be a nightmare to add an another collection to egalize.