Pastiche rhymes with:
ashish, bayerische, eash, friesz, heesch, judishe, leash, liesch, macleish, mcleish, mcneish, quiche, rajneesh, sheesh, treesh, unleash
Pastiche sounds like:
packets, packwood's, pact's, pacts, pagoda's, pagodas, pas-de-deux, pastas, pastes, pastiches, pasts, pectic, pesetas, pestka, pests, phagocytes, physicists, piaget's, pickets, pickett's, picts, pistachio, pistachios, pockets, posits, post's, post-attack, postage, postdates, posts, psychotic, pussycats