Looking for some 'grass

Jim,
Glad you asked.
One of the best Bgrass Cds is John Reischmann, South of The border.
Performance is excellent, musicians play with power, passion and fire. Tunes are mostly original with a Latin, Jazz flair, but it is Bluegrass music.
It is not on LP, but the quality of the recording is also excellent. One mic with the mandolin, banjo, guitar, fiddle and acoustic bass. As each takes a solo, they step closer to the mike. No vocals
I would be happy to send a few cuts on a burned CD so you can be convinced it is well worth a purchase.
Similar to Grisman, but more fire, IMO.

A little hard to find, but worth it: New Grange, a short-lived all-star band comprised of Darel Anger, Tim Rice, Alison Brown, Phil Aaberg, and Mike Marshall. Each is a virtuoso on their instrument.

The Be Good Tanya's - I like "Blue Horse" and "Chinatown" but their new one's pretty good too, though doesn't seem as well recorded.

The Wailin' Jennys are new to me but definitely worth checking out.

Anything at all by Gillian Welch - You cannot go wrong there.

Abigail Washburn, "Song of the Traveling Daughter"

"Oh Brother Where Art Thouw" and the companion version..."O Sister" both have a fun cross section of stuff you may like. The former is an excellent soundtrack.

Speaking of great soundtracks; the soundtrack to the film "Songcatcher" is also excellent and right along the same lines as this thread, but more right to the roots of it.

Jax2, I'm a big fan of all of your suggestions, but there's very little bluegrass in those selections. The "Oh Brother" soundtrack and the popularity of Alison Krauss has watered down the definition of what passes for "bluegrass" these days. I've been listeing to Alison Krauss since she was a teenager and I'm a huge fan. Her early albums are certainly bluegass, but in the later years not so much. The best traditional bluegrass band today is the Del McCoury band. Instrumentally they are fantastic, though they wear on me after a while. My favorite bluegrass band of all time is probably Hot Rize. Great instrumentalists and vocalists and great songs.

Jsaah, its Tim O'brien in New Grange, as opposed to Tim Rice. Anything by Tim O'brien is good (he was in Hot Rize), though his stuff is not all bluegrass either. You may have been thinking of Tony Rice, who is one of the all time great bluegrass guitarists and vocalists, but sadly lost his voice many years ago due to a medical condition. But Rice has some great bluegrass albums.

Other good bluegrass recommendations are Doyle Lawson and Quicksilver, Blue Highway, Mountain Heart, Front Range, and the Nashville Bluegrass Band.

Claire Lynch, Rhonda Vincent, Dry branch Fire Squad, Grascals, Cherryholmes, Flatt and Scruggs, Olabelle Reed, compilations from Rural Rhythms, Smithsonian amd Rounder (though these can be old timey music), any Wayne Henderson cd for some bluegrass guitar music, the Pickin' On series, especially Pickin' On Led Zepelin, any of the Bluegrass Albums by the Bluegrass Album Band. Heck, just go to the local internet book and music seller and type in "bluegrass music". The ones I saw on the A site that came up were compilations I have and were all good, though like I said, they may be old timey. Have fun!