Long,
Sorry, I couldn't resist...
Now, to get more serious, I have a 12" factory bbl with muzzle tamer. Mine has shot it's best groups with the Hornady 200 gr round nose. It will keep 5 shots right at 1" from a benchrest. I consider that just fine for hunting purposes. That being said, I have broken a Bushnell trophy scope on that barrel. Adjustments went south on it. It is now scopeless, but I have swapped scopes on my JDJ, and plan on putting my old 3x TC scope on it. I know the elite is a better built scope than the trophy, so I wouldn't expect you to have any issues with your scope on a 35 Rem bbl.
I have heard lots of folks saying that the factory 35 Rem bbls have headspace issues. Too many times to not believe there is something to it. I have not seen this problem with my barrel, but I'm sure there must be some out there with "issues". If you get a barrel with this issue, you can fireform your brass initially with the bullet seated slightly into the lands and avoid those problems. Just use care in resizing so as not to set the shoulders back during sizing.
I can duplicate 35 Rem carbine loads safely from my 12" bbl. This in my opinion, with a 200 gr bullet would be a fine black bear gun out to 150 yards or so. Also fine for deer as that 200 gr round nose is meant to open at Rem velocities. I think the caliber choice would be a good one. For whether to go custom or not... well, that is up to you of course. You will be less likely to find a bbl with issues if you go custom, but you will be more likely to take a harder hit to the wallet for custom too. I'm afraid you'll be the only one that can decide which option is best for you.
I don't see 35 Rem's come up for sale very often, either factory or custom. The factory bbls can't all be turds, or you'd see a non-stop cycle of buying and selling of them in the classifieds. You can also give Ed a call at Ed's TC's, he's probably got 5 or 6 of them over at his place as we speak.