Already you did it...The code you gave has the way to extract the data you want.
hsp = surf(linspace(-2,2,20),linspace(-2,2,20),zeros(20)+1);
rotate(hsp,[1,-1,1],30)
xd = get(hsp,'XData');
yd = get(hsp,'YData');
zd = get(hsp,'ZData');
delete(hsp)
[x,y,z] = meshgrid(-2:.2:2,-2:.25:2,-2:.16:2);
v = x.*exp(-x.^2-y.^2-z.^2);
hss = slice(x,y,z,v,xd,yd,zd);
xs = get(hss,'XData');
ys = get(hss,'YData');
zs = get(hss,'ZData');
cs = get(hss,'CData');
figure
surf(xs,ys,zs,cs) ;
You have the data xs,ys,zs,cs in your hand now.