pew.. I just played a little with selections and .. It looks completely foolish, but that here just does what was simply impossible for me until now:
CODE
{
string $sel1[] = ls -sl;
select $sel1;
GrowPolygonSelectionRegion;
string $sel2[] = ls -sl;
select $sel2;
}
It grows selection.. fine, but this you can undo correctly!
I heard that will be standart in Maya 7. 