I was like you. For many years I hunted whitetail with a rifle, and a bow. Then I decided to buy my first handgun and go out "doe" hunting with a handgun instead of a rifle. My first handgun was a Smith & Wesson model 629 DX Classic 44 magnum. After I bot this gun and began shooting it, I then got into reloading because the price of 44 ammo was costly, and I was having too much fun shooting the darn thing. Now I reload everything from handgun to rifle.
I have found that the 44 mag is not too much in terms of recoil to handle. I have also found that it is an excellent round on whitetail deer using a hollowpoint bullet. Now, the 357 will also kill a whitetail. I can't tell you this from personal experience, but just from what friends who own them have told me. However, should you choose to buy a 357, I would say don't get one with a barrel less than 6" as you will lose velocity and accuracy. That being said, my Smith DX has a 6.5" barrel.....but it is deadly accurate to 100 yards.
If you don't reload I don't understand the "want" or "need" to have a 357 handgun because you want a 357 longgun. Perhaps if you did reload I could understand the convience of one set of dies, one type of powder, one brand\weight of bullet...ect....but if your buying off the shelf bullets, I don't see the reason you can't buy a box of 44 mag bullets and a box of 357 mag bullets.
Now, as for double action vs. single action, that's probably a matter of how much you have to spend and personal preference. I will tell you that for hunting situations, 90%-95% of the time, I have shot game using single action. It's not that often that I use double action. So...what does that tell ya? However, single action pistols are a PITA to load as the cylinder does not "roll out" like a DA revolver. You have to do a "one-at-a-time" punch out and put in deal. I'm spoiled so that would drive me nutz.
Also, from what I have read, (and I've never hunted hogs) hogs are a tough customer. The guys who hunt 'em say use any caliber handgun you like.....as long as it begins with a "4". So, a 44 mag, 454 casull, 460 Smith, 480 Ruger.....you get my point.
As far as handgun scopes are concerned, I would put on what I have had on my Smith 44 since I bot it. A Simmons Prohunter variable.
http://www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=113584 This handgun scope has taken a pounding and always held zero for me. I shoot nothing but full power 44 mag loads from my DX and this scope has never failed. I use the 6x at the range to punch holes in paper, and I hunt with the scope on 2x. For a $100 scope (if you wait, Midway always put's it on sale for $100) you just can't beat it. Mount it with Burris Signature Zee rings.
http://www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=416175&t=11082005 These rings have the synthetic insert that (I think) help cushion the scope against hard recoil, and they help center the scope alignment.
Well....that's my two cents. You make the call. If you hog huntin you may loose a few with the 357....but I'm no expert on that. Perhaps the hog guys will chime in and help there.
Dave