The Tecan MIO2 is significantly smaller:
https://forums.pylabrobot.org/t/mio-shaking-incubator-tower-experiences/942
https://www.google.com/search?q=tecan+mio2
And the Hamilton Incubator Shaker is, too;
Multiple units of the Inheco Single Plate Incubator for standard low-profile plates and/or deep-well blocks can be stacked:
Hamilton robots can only access the bottom two positions in an Inheco SCILA because the top two are too high for the iSWAP (on a STAR) or Integrated Plate Gripper (IPG, on a STAR V or VANTAGE).