Most manufacturers don't offer a lefty stock, it's usually a special order. Most, if not all makers offer a uni stock for both type of shooters on all of their models.
If you want a lefty there are several guys that make custom stocks, but as you may know already, they're not cheap.
As far as what caliber for hunting and plinking, it's up to you. A .177 will kill a bunny just as dead as a .22 would. Personally all of my springers are .22's, I don't hunt, but I like to be prepared just in case I do need to kill something that a .177 can't drop. And if my .22's aren't enough, I can just pull out the powder burners.
Google, Yellow Forum. Read every post, that's what I did as a newbie air head 10 years ago, you'll learn a lot.
