The A380 has three vanes right in front of the flight deck on top of the nose which should be able to measure sideslip. No idea if it is indicated.
The skid/slip indicator on modern PFDs however is pretty sensitive, but alas has no scale to show degrees of sideslip. In normal cruise with a correctly rigged airplane there is no indicated sideslip and no control surface deflection. While thrust is not directly displayed (again, it is in the A380) the electronics are there to know and set it regardless and therefore equal thrust is nowadays a reality as well.
A yaw string of course is quite nice and extremely accurate. Having flown with strings but without engines it was a direct performance instrument and and became second nature to keep centered in those, hmm, 15 or 20 years i used it.