You'll have to build it yourself, or have someone build one for you. Thus far, there are none on the market that I know of. If the music stand slot of the keyboard was not so unreilable, I would design one that would fit directly into the slot. Unfortunately, the stands that fit in the slot seem to work themselves out, even with just a lightweight music book on the stand. I'm working on a combination slot stand now, and with luck I'll have it done by the end of the month. This one will hold the laptop, two small Yamaha speakers and have a thin storage space for the power packs and surge protector inside. The entire stand should fit directly into the laptop case beneath the laptop. I post photos when it's completed.
PSR-S950, TC Helicon Harmony-M, Digitech VR, Samson Q7, Sennheiser E855, Custom Console, and lots of other silly stuff!