At least in Dangerous Covenents and the Core Rulebook, I have not found any sort of sniper rifle stats. Are they in any of the other sourcebooks?

If not, here are my stats. (This is a great weapon for players have the assassain specialization)

Sniper Rifle:

Skill: Ranged-Heavy

Damage: 8

Range: Extreme

Crit: 2

Specials: Accurate 1, Vicious 2

Cost: 1,500 Credits

Encumbrance: 5

Hard Points: 4

Also, it might get a setback die when a short range, for being unwieldy in close combat. Is this weapon a bit too pricy? Too overpowered? Not good enough for the price? Feedback would be appreciated.

There is the weapon attachment you could just attach stated out to any blaster rifle and make one. There are some long range weapons in a number of the splatbooks. Enter the Unknown has a couple as I recall.

Enter the Unknown has the E-11s Sniper Blaster Rifle.

Just do what I did when making an NPC sniper and give a Heavy Blaster Rifle Extreme range, but without Auto-Fire, in fact, on its own, the Heavy Blaster Rifle is kind of a sniper rifle. Failing that, give a regular Blaster Rifle a Marksman Barrel. Long-ranged snipy fun for everyone

The AoR Strongholds book has the Verpine Shatter Rifle which would make an effective, but fragile, sniper weapon.

Enter the unknown also has the model 38 slugthrower rifle and the hurt book has a weequay blaster lance which I've reskinned a lot as a sniper weapon (dropping that blade)

Standard blaster rifle + Marksman Barrel = sniper rifle. If it's for an NPC, that's pretty much all you need.

If for a PC, then add in that scope that reduces the difficulty of attacks at Long and Extreme range, and maybe the attachment that boosts damage so that you can get further damage and ranks of Pierce.

I once played a h-k modle assassin droid who had a blaster rifle modded with the marksman barrel and the scope making this very useful in long range combat.

Just do what I did when making an NPC sniper and give a Heavy Blaster Rifle Extreme range, but without Auto-Fire, in fact, on its own, the Heavy Blaster Rifle is kind of a sniper rifle. Failing that, give a regular Blaster Rifle a Marksman Barrel. Long-ranged snipy fun for everyone

Indeed. The HBR can easily be made into a sniper rifle or machine gun depending on how you use it. IMO its also like a Barret .50 cal, if it had a full auto option.

A HBR with either an Augment Spin Barrel or Marksman Barrel, and then a Telescopic Optic Sight. If you are feeling really nasty get Jury Rigged on there for another hard point and you can have all 3.