What is it specifically that you need to emulate about the Powerbook 170? For better-than-68000 emulation the go-to emulator is usually Basilisk II, which simulates a generically "Quadra-ish" machine. (With the primary limitation being it doesn't do 24 bit addressing, which means some old programs might have trouble and it won't run System 6. You can of course always revert to regular vMac to run those edge cases.)