Gary:
Unfortunately, the first 10 years or so of Ralph's career has not surfaced in LP form. I don't think anyone has attempted to document everyone he recorded with before the late 50s. I am not sure who all he recorded with, but I don't think any of the LPs he is known to be on were released before 1958 or 1959, maybe even later.
He supposedly spent time with Merl Lindsay and The Oklahoma Night Riders when Lindsay was based in Southern California (late 40s, maybe early 50s), but I don't know if he ever recorded with that band.
He did a lot of session work into the early 60s for "unknown" local LA artists who never made an LP--it's all on 45 rpm and mostly for small labels.
I believe he did some sessions with Skeets McDonald on Capitol in the late 50s. The original McDonald LP "Goin' Steady With The Blues" is difficult to find, but the tracks have been reissued.
I'm not sure, but that is likely him on at least some of the recordings on Bobby Austin's two LPs for Capitol. As far as I know, they have never been reissued.
He did several great singles with Jan Howard (without Wynn Stewart) on Challenge around 1960. I don't think these have been reissued.
He had a 45 rpm release under his own name on Challenge circa 1960 called "Moonshine". Good luck finding an original, but you might be able to locate an LP or CD on which it was later reissued.
Here is one must have, by a classic country singer who passed away maybe 30 years ago. Ralph is all over it. Nearly all of the songs were recorded in LA around 1960:
http://tinyurl.com/ku9mry
I think the LP he did with James Burton in the mid 60s is also available on CD. It is called "Corn Pickin' and Slick Slidin'" if I recall correctly.
And here is a pic of Ralph with a Rickenbacker in 1947 that you may not have seen: