How much LF info on LPs?

As usual,Tom is correct.
There are so many misconceptions about analog it isnt funny.
Try analog,see for yourself!

I'm not sure where audiophiles got the impression that LP's don't contain low frequencies, but Twl's comment is on the money. I have some LP recordings of pipe organs which have frequencies that reach as low as my pair of Vandy 2Wq's can reproduce, which certainly means down to the 20-Hz range. I have also read liner notes on several of the Telarc LP's that I own that state there are frequencies down to 16 Hz.

Having said all this, that does not necessarily mean that a given person's analog system will be able to accurately reproduce frequencies down to the 20-Hz range. The turntable itself must be rock solid and well isolated from acoustic vibration; and the tonearm/cartridge combination must be able to accurately track the wide, low-frequency undulations of the LP's grooves. Extreme low frequencies require very wide groove on the LP, and this is a severe test of tracking ability.

IMO, as usual, the vast majority of mass-market LP's contain truncated or highly compressed bass. Especially as one moves towards the inner grooves; especially the innermost track. Bass equals groove excursion, and that equals expending vinyl floor space... Having said that, in my limited experience w/ CD's, there doesn't appear anything magical about bass on CD's.

I've just run a low end test w/ the Rives test CD/Radio Shack meter, and believe me, the room structure is the final factor in bass response. Vinyl is capable of some *very nice bass, but the room acoustics are what makes or breaks the situation...

I wonder if you are refering to the RIAA curve? It was learned a long time ago that low frequency signals require a lot more space on LPs than do higher frequencies. For that reason the curve was introduced. Any reasonable phono stage is going to replace the LF that is reduced in the pressing.
TWL is exactly right is his comments. LPs contain more bass than CDs are capable of holding due to the terrible design flaws incorporated when building the originals. That is one of the reason new formats like SACD and DVD-A are coming out. The manufacturers are trying to make machines which are capable of reproducing sound as well as a *basic* turntable. Digital has a long way to go to get there. They will probably never match the sound quality of better turntables!
The signal is there in vinyl, you just have to be able to retrieve it!

As stated above, there's no question that vinyl can go quite low, but deep bass is one of the few areas, maybe the only area, where Redbook standard CDs can actually exceed the performance of well pressed vinyl. Very deep bass on vinyl is constrained by the physical limits of the groove width. Loud music requires wide grooves. Deep bass requires wide grooves. The problem arises when you try to have loud deep bass because you'll fairly quickly run into playback tracking problems. At 60Hz this is not an issue and I believe it only becomes serious once you start to get below 40Hz. There's also the issue of running time per side of vinyl. Large amounts of deep bass cuts down the running time available per side. As a practical matter it is very rare for mastering engineers to purposely press vinyl with sub-30Hz info. Also deep bass on vinyl is always (100% of the time) mixed mono. Redbook CDs can have true channel independence down to any frequency.