(defun thunk-component-args (prefab-spec)
  (flet ((split-body (body)
           (au:partition #'symbolp body :key #'first))
         (thunk-args (args)
           (loop :for (key val) :on args :by #'cddr
                 :collect key :collect (lambda () val))))
    (multiple-value-bind (components children) (split-body (rest prefab-spec))
      `(,(first prefab-spec)
        ,@(loop :for (name options . args) :in components
                :collect `(,name ,options ,@(thunk-args args)))
        ,@(mapcar #'thunk-component-args children)))))

;;

(mapcar #'thunk-component-args '(("foo" (foo () :arg (list 42)))))