ionus, when someone says they don't see climate scientists discussing a parrticular topic, it's usually because that person hasn't looked, not because it hasn't been examined and debated. Here, for example, is the IPCC's summary of current research on volcanoes (including Pinatubo):
http://www.ipcc.ch/ipccreports/tar/wg1/175.htm
(I had to change the 175 page number in the URL to 176 and 177 to get the succeeding pages in the section).
They make the same point I did, while a major eruption may have an effect for a year or two, maybe three, its output of aerosols and particulates drops off rapidly and its effects diminish rapidly. They don't talk about Tambora, but that was probably the largest eruption in the last thousand plus years at least. It was the probable cause of "The Year Without a Summer" in much of the world in 1816, and a cold 1817, but by 1818 things were pretty much back to normal. It had no lasting impact on climate.
To give some sort of scale, Pinatubo's effect on temp after four years was roughly half the effect of the cyclic change in the sun over its (nominally) 11 year cycle, and that solar effect is so small it's hard to pick out of the background noise of interannual weather variability. And even that small effect kept diminishing over time.
Volcanoes, in short, and their effect on climate, like all the other relevant variables, have in fact been researched and discussed. They just don't have a significat effect.