Looking for LEFT handed holster suggestions for the following open carry
S&W 642
S&W model 17 " barrel
Ruger SR22
M&P Shield 9 and 45
Thank you in advance for suggestions.

DeSantis and Simply Rugged both have SouthPaw holsters readily available.

Bob

RJM ,what's your thoughts between the two ,quality ,comfort ,durability ?

About equal but in different ways.

I like the DeSantis Speed Scabbard and Mini Scabbard for concealed carry. They make them for almost all my guns so regardless of what I am carrying it is always in the same place.

For hiking, hunting and field carry I like the way the Simply Rugged rides.

The leather is thicker on the SR holsters but to me the DeSantis is just as durable...

Both are also very reasonably priced...

Bob

For the Ruger - check this out: http://shopruger.com/

I just received a LH holster for my Ruger Single-Six from that source.. Nobody can beat the quality for the price.. I was totally surprised.

Midway has Bianchi holsters on sale right now. Several models in left hand.

I can make you a left-handed holster for the 642 and, depending upon which model you've got, the M&P 9. Several members here can vouch for my work.
PM me if you wish and I can e-mail you some pictures of my work.

I'm not the most experienced when it comes to holsters, but I like the Wilderness Safepackers, and most everything they make has a left-hand option. I think they are a great all-around holster, but are especially in the winter time. When wearing a jacket or even an un-tucked flanel shirt, most know you need to practice lifting the garment with your weak hand to draw the weapon with you strong hand. With the Safepacker, you don't need your weak hand at all - just reach down and unclick the buckle with your strong hand. When you lift its flap it automatically gets you jacket/shirt out of the way, then pop your strong hand down and your gun is in your hand ready to go. This is especially useful when walking my dog. I hold her leash in my right hand and would never have to let go if I were to ever have to draw my firearm.

For full-size revolvers, I do like a nice leather holster around town because the larger Safepackers look big on a belt. But out in the woods, I don't care about what I look like. I care about function and I've been through some nasty desert brush where my Safepacker took the brunt of the abuse and kept on going, but my firearm was nestled inside safe and untouched, but ready to go at a moment's notice.

Interesting

With the possible exception of the SR22 the handguns on your list are common/popular enough that any holster worth having is available for either hand.