Do you like DIY? Plenty have done it to the eq5 (incl. me) and some to the vixen gp. Works beautifully
https://groups.io/g/onstep
Edit: David just beat me to it. To mount the stepper I started using aluminium and a nema17 bracket. I then 3d printed the bracket
https://groups.io/g/onstep/topic/14406044