I own several ARs in 6.8 and its the hunting rifle of choice for my oldest daughter. It does a good job for what is was designed to do. I consider it about a 300 yard rifle for deer and hogs.
You hit on the 1 weakness this cartridge has... Ammo availability. I have bought online from Silver state Armory and have been happy with their offerings. I also have found Sellier and Belloit on the shelves at the local Cabellas as well as Hornady on the shelf at my LGS. Via my LGS, I have also purchased 200 round cases by them, ordering from their distributor without much difficulty, pre panic.
Federal is supposed to be producing a fusion round this year as well, which may help availability and perhaps lower prices. That will bring another name to the list of Remington, SSA, S&B, and Hornady offering factory loadings, that I know of (there may be others).
Thus far, my favorite hunting round is the 120 grain Hornady SST. Thus far, it has produced impressive wound channels in the 3 Texas deer it was pointed at. Each was a 1 shot kill with the bullet placed where it should have been.
Reloading would make this a more cost efficient round. I am preparing to make my first steps into metallic cartridge reloading for that primary reason. Pre panic, cost was approaching $1/round. Now, a look on Gunbroker or the ammo search bots will show upwards of $1.50/round.
There have been at least 1 bolt action made for this cartridge: a Remington 700. I've seen on Gunbroker other rifles, but all have been used and raised my suspicions that they might have been rebarrelled. In a bolt action, it would be a mild recoiling rifle with deer and hog capability, but if I were going with a bolt action rifle, there are other calibers out there that will do the job, with more ammo availability, and often with better range and performance.
If you are looking for further information on the 6.8, checkout 68forums, a board much like this dedicated to the 6.8. Lots of fanboys over there, so take your grains of salt with you.
Another round to consider if you are looking for an AR with more punch than 5.56 for deer or hog would be 6.5 Grendel. In addition to Alexander Arms and Hornady loading factory ammo, Wolf announced they would be offering steel cased loads at comparable prices to their 5.56 offerings, making for a cheap practice/plinking round, something you will not find in 6.8 SPC. It also retains velocity better beyond 300 yards if you are interested in stretching out for paper punching at longer distances.
, any jumps to other threads from the mods is welcome.