It's hard to imagine they'll build bigger versions that the 70,000 kg one. They are way behind schedule on the first version, and still don't have a compelling mission commitment.

There is no doubt they could send some pretty large payloads to Mars with the SLS, esp. the later block designs. The question is whether congress is going to commit to the tens of billions to build those designs and actually launch manned missions to other planets or the moon with them.