I just got my Voyager RME and am intrigued by the versatility of the Touch Surface as I read the manual. Sadly and obviously the rack mount edition has no touch surface.
Being woefully ignorant regarding my options, can someone recommend a third party touch surface controler?
I do believe that Paia offers a DIY kit for a touch pad. Fairly reasonably priced, I’m sure. Well worth looking into if you work well with a Weller. 
THeres always the Korg Kaoss pad.
I am also in favor of Moog making a dedicated touch surface for those with RME’s and Old Schools, perhaps they could do it in a MoogerFooger housing and sell it under the conntrollers section. THat and Dr. Moog already made one.
I don’t see why said touchpad couldn’t be used with the Phatty either, but I think it would be a question of how they would attatch it to the Vx351 without it being routed through the computer cable attatchment.
THey would probably have to make a VX-353 for the Old School.
Thanks for the tips. I didn’t realize PAiA made a touch pad kit. I’ll look into that as well and the Korg K.O. pads.
Now if you are interested theres also PC joystick controllers if its simply the X-Y axis you are after.
THat and the buttons fire gates.
Nothing like Atari Style synth control.