Hi and welcome to the Bome community!
This posting is closest to what you are looking for but could me modified to meet your needs. If you want to run it on BomeBox, then you would also need to purchase Bome MIDI Translator Pro which runs on Windows PC or Mac and then upload it to your BomeBox for execution. At that point you could disconnect your computer.
Right now there is a shortage of BomeBoxes, We expect to get a limited quantity this spring and then sometime in the summer, BomeBox 2 will be rolling out. Use the contact form if you want to get on a waitlist for BomeBox 1. If you want to wait for BomeBox 2, then you can subscribe to our newsletter and will be notified when they are avaiable.
And yes, it is possible to use a single control to send multiple SysEX messages. I imagine, that we would add rules to adjust the value of each SysEX drawbar message based on the value of the incoming CC.
Steve Caldwell
Bome Customer Care
Also available for paid consulting services: bome@sniz.biz