CorSec Engineering releases 60mm Square Bases for the Omni-Stand system:
From their post:
These bases are 60mm square and provide a little more stability for larger ships. They are perfect for Dreadnaughts. Bases come with firing arcs and without. They are compatible with the entire Omni-Stand line of flight stands.
Without Arcs – $1.24 each
With Arcs – $1.74 each
Volume discounts available.