As a 218 in this instance would essentially be a switcher and method of control, maybe at least try it. The DSP9 can still be RS232 controlled, just not with Vitual MSR. I am working on a Crestron module to control the XE and DSP9. I am not sure how to create a iPad app but maybe someone who does could jump.in.

www.cmbintegrations.com
One step from the Presidency
#1 Trinnov Altitude 32-8-16, 271, 8000XE, 7200SEHC, 7200.2, Seaton F18, JL Fathom F113, Revel w990's, Kef R7, ATI 528 Amp, JVC RS4100K, SI screen. Roon Nucleus+, Eno AG, Eno M link, 218.
#2 Mark Levinson No5105, Ayre VX8 and CX8, Vandersteen Treo CT, Preamp varies.
#3 Meridian Ellipse