works.rkt

#lang racket/load

(module st racket  
  (define state (box 0))
  (provide state))

(module m1 racket
  (define l (list #'l))
  (provide l))

(module m2 racket
  (require (for-syntax 'm1 'st))
  (define-syntax (mac stx)
    #`(begin-for-syntax
        (module* sub #f
          (set-box! state (length #,(car l))))))
  (provide mac))

(module m3 racket
  (require 'm2)
  (mac))

(module m4 racket
  (require 'm3 (for-syntax 'st))
  (begin-for-syntax
    (dynamic-require '(submod 'm3 sub) #f)
    (displayln state)))