clocker wrote
Is it possible to implement the 8-way 16-bit mux using some of my newly created 4-way 16 bit mux gates?
Yes, this is a good approach. The 'sel' signal on the 8-way is a 3-wire bus so you will need to connect only a portion of it to the 2-bit 'sel' of the 4-ways. Read the Buses section in Appendix A (A.5.3) to learn how to select only a portion of a bus. Hint: Mux4Way16(sel=sel[something], ...
--Mark