Horizantal Cross Draw

In 1968 Don Hume Made a Cross Draw holster for my S&W Model 29 / 4" barrel. It was simply two strips of leather stitched together with two slots cut at the end for a belt. I carried that big weapon everywhere under a light jacket, and no one knew. I've been looking for one like it to fit my Sig P250 SC. Any Ideas.

Andrews has one (http://www.andrewsleather.com/traditional.htm) called the Carjacker Crossdraw:

http://www.andrewsleather.com/carjackerx_a.jpg

Cross draw from Mernickle. It looks like what you are describing.

http://www.mernickleholsters.com/ps/ps10dar1.html

What does the "tension retainer" do? Is it just a friction/pinch fit against the trigger guard?

Hume no longer carries it?

http://www.donhume.com/index.php?main_page=index&cPath=413

tipoc

"What does the "tension retainer" do? Is it just a friction/pinch fit against the trigger guard?"

It's a screw that has a soft rubber or plastic tube spacer in between that you can tighten or loosen for the retention fit that you like....and yes, it works like you mention.