Levels equivalent in Lightroom

In a word, No. Obviously you can use the WB-eyedropper in LR to function similarly to the graypoint eyedropper in PS, but otherwise:

I use Auto Tone to see where LR wants to set my black-point with the Blacks slider, and you can turn on the dark-clip/white-clip indicator triangles in the histogram to see where things are being pushed beyond the black and white clip-points as you play with the other toning sliders, but because LR is non-destructive and more than one slider can be adjusted to affect the black and white points, there would any number of toning slider values that LR could use to satisfy a black-point-set or white-point-set operation like you can do in PS so it doesn’t try. This is left up to the user. AutoTone is the closest LR has to an operation that sets all values simultaneously, but you cannot choose what portions of the picture to use to do this nor know exactly what it is doing.

If you are talking about using the black and white-point eyedroppers to set the color-balance at the low and high ends, then I have often wanted a way to set the split-toning sliders via eyedroppers, which is almost impossible to do, now.

Back when ACR was the only game in town, a suggested procedure for setting toning sliders was to set the blacks slider to determine your black-point, then set the exposure slider to determine your white-clipping and then use the brightness and contrast sliders to affect more the midtones, although they also will push things beyond the black and white clipping points. One thing that makes this suggested procedure more difficult in LR is that the histogram in ACR is determined by the output colorspace you have set and the shipping indicators match what the output will be, but in LR the histogram reflects the internal working colorspace of LR, so something showing as not clipped in LR’s histogram might actually be clipped in the output image when you set the colorspace in the Export panel and there’s no way to proof this beforehand. I hope LR 4 will have something to help with output-colorspace feedback but people have been wanting this since LR 1 and so far it’s been too difficult to decide what to do.