I searched for a long time before happening on this combination of:

Gator Frameworks Deluxe Two Tier X-Style Keyboard Stand

On-Stage KSA8500 Deluxe Keyboard Tier

The KSA8500 fits perfectly into the 2nd tier of the Gator x-stand. The feet on the x-stand are wider than normal and provide for a really stable platform.

I alternate between loading a Yamaha MOXF6 (61 key), and a Yamaha P121 (73 key), on the bottom tier, along with an Arturia MiniFreak on the 2nd tier and a pair of Yamaha Refaces (YC and CP), on the 3rd tier.

I play standing up but you could adjust the height for seated play if you like.