Looks like I-Cycles in Japan sells the 650B Grand Bois Papillon rim in 32-hole (double walled) and 40-hole (single walled) versions:
https://cyclesgrandbois.com/SHOP/gb_r_b_pw.html
https://cyclesgrandbois.com/SHOP/gb_r_b_p.html
Edit: Looks like the 700c version also can be found in 40/32 drilling:
https://cyclesgrandbois.com/SHOP/gb_r_c_p.html