"...attributable to ice melt. Just want to warn you to be careful with that, as it may not be true. Adding up observable (plus reasonable assumptions on non-observable) ice-melt does not account for all of the sea-level increase. I think I heard more like 25% or 50%. " - alcaray from:
http://www.habitablezone.com/space/messages/379466.html

Determining the rate of global sea levels is difficult. The compexity is such that one simply can't determine sea level rises if one has only measured an area or many areas for less than 10 years:
"The conclusion that can be drawn from all of this is that 50 years is the absolute minimum sea level record length that should be considered in an analysis of global sea level rise or acceleration from tide gauge data alone. Fortunately, more long records are becoming available in many parts of the world because of the large number of tide gauges installed in the years following World War II. In addition, we shall see below that it may be possible to compute from other data much of the troublesome interdecadal sea level ``noise,'' and eliminate it from the signal. The next 10 years should see much progress in the problem of separating vertical crustal movements at tide gauge locations from interdecadal fluctuations of sea level. "
....
"Assuming now that an average value of global sea level rise can be, and has been, determined for about the last 100-150 years, the next consideration is whether or not this value has undergone significant change over that time. Fortunately, determining acceleration of sea level change is less formidable than the linear problem, at least in regard to PGR and tectonic plate boundary effects."
http://www.agu.org/revgeophys/dougla01/node3.html#SECTION00030000000000000000

So, my statement is in regards sea level rises reflecting glacier melt is assuming one is measuring the sea level accurately [and therefore accounting for all the variables that make measuring sea level difficult. And according to above one requirement do this is that the locations which you are measuring from need a history of recording of over 50 years.]
But I don't disagree with: " I think I heard more like 25% or 50%." I think I would tend to favor more towards to 50% or maybe more, but it's possible that it's nearer the 25%.

[I also don't think we are going to get any help from Satellite measurements, they don't appear to be accurate enough, but perhaps if there is a long enough period of satellites taking measurments they can improve upon this.]

It doesn't appear that we can accurately measure sea level rises even if there has been long term measurement from one to the next, but I would guess that if instead of yearly you extend this to be 2-3 years I think we could get a close enough measurement to distingish global glacier melt with a fairly high level of certainty.