How many pixels to reach lenses resolution limit?

As we all know support (film or digital sensor) resolution isn't the only limiting factor in final image resolution.
Even the best lenses have limited resolution and beyond a certain point, no mather how much pixels we have, the image quality will not improve, at least with the lenses we have today.
Does any one knows how far do we are from that point?
Does a 20MgPixel camera still has enough glass resolution?
Any thoughts on this?

The number of pixels is only indirectly related here.
What really matters is the size/density of the pixels (increasing the number of pixels by increasing the sensor area will not impact this, although it will put pixels into the outer areas of the image circle where the lens resolution is not necessarily the same as at the centre).

In any case, you're not going to get a cut-n-dried answer, as different people have different definitions of "the limit" for different purposes. The new 8Mp cameras like the Sony F828 with 2.7um pixels are quite different to the EOS 10D with 7.4um pixels (715% of the area area) and the 1Ds with 8.8um pixels (1062%). The behaviours of these sensors are different, but still acceptable for many people.

Thanks four you answer David, but my point is: lenses resolution is measurable and usually translated in lines per millimeter or something like that. If a good lens has a resolution power of around 100lines/millimeter is it desirable to have at least the some amount of pixels per millimeter?
That would imply for a 1:1 sensor 2400x3600pixels witch is not nothing very spectacular.

Does this make any sense?

If the 100 lines per millimetre are 100 black lines with 100 white spaces in between them, you actually need 201 or more pixels per millimetre to resolve them. That's 35 Mpx for a 24x36mm sensor.

-Paul