Craft me a bush hunting rifle

I guess I'm about to prove I'm getting old or just a contrarian but I don't buy into this 'must be 16-18 inches' deal.
As has been pointed out short barrels are more damaging to your hearing and once you have shorten them you can't put it back on.
I'm no expert bush hunter however I hunt with a 22inch suppressed 7x57 and a 21inch suppressed 7mm08.
The extra 4-6 inches makes no difference when it comes to getting hung up in supple jack or bush lawyer because you have your rifle in hand.
A lighter rifle however is definitely desirable.
When I faced the decision your trying to make I ended up just getting my open country rifle threaded and suppressed. They asked if I wanted it shortened, I said no.
That would give you a do everything setup depending on your scope.

I guess it comes down to how you carry the rifle too. Id imagine for someone that always carrys it in their hands like alot of people do, a longer barrel wouldnt be too much of a hinderance. For me personally, i use a sling and spend a fair bit of time with the rifle over my shoulder when im walking/moving through areas where im not expecting to see a deer. If something does pop up unexpectedly, i grab the grip of the rifle and slide it around my shoulder on the sling strap, muzzle travels down towards ground then up & shoulder it which i can do smoothly and quickly. Long barrel up above your head can be a pain in the ass when walking through thick scrub. Im also not the strongest of blokes as far as arm/upper body strength, so a short light rifle is much easier for me to hold shouldered & steady for what can seem like an eternity while waiting for a shot to present itself in thick bush, I know some of my other longer rifles that are more nose heavy i would struggle to hold steady for any extended period.

To me, shortening a rifle to suppress it is not just about it's length and "handiness" but just as much about it's balance. A 22" barrel with a suppressor on it handles a lot differently to a 16" barrel suppressed. Not only when you shoulder the rifle but also when you carry it in the hand (or slung).