Multidex rhymes with:
rolodex, tridex, adaptaplex, adaptec's, ameritech's, ametek's, amex, ampex, annex, apec's, apex, armtek's, audiotex, avtex, aztecs, banamex, berlex, biotechs, bottlenecks, cemex, centex, cineplex, comex, comtrex, crownx, cybersex, cytotechs, datarex, defex, discotheques, duplex, entex, equitex, eurochecks, eyetech's, fanech's, finex, gatx, gendrisek's, genentech's, gtech's, hyponex, inmex, intex, kaisertech's, latex, medarex, mediplex, memorex, memtec's, metex, methanex, metroplex, middlesex, multiplex, natec's, neorx, nymex, nynex, opec's, oraflex, paychecks, paychex, pemex, pewex, pillowtex, playtex, portec's, prentnieks, qintex, railtex, rednecks, rolodex, roughnecks, scitex, simplex, starplex, steinbeck's, stratoflex, superx, symantec's, syntex, teleflex, telex, telmex, tenrecs, timeplex, tridex, trintex, truex, turtlenecks, unisex, ventritex, vertex, videotex, visx, wedtech's, westtech's
Multidex sounds like:
maladich, maladies, maldutis, maltais, maltase, maltese, maltose, malts, maltz, maultasch, melodic, melodies, melodious, melts, meltz, miladic, mildews, miletich, militia's, militias, milledge, millets, milodic, mladic, mladic's, mlotok, molds, moltz, monolithic, monoliths, moulds, multitask, multitudes