Unavailable rhymes with:
available, available, available, inhalable, salable, saleable, unassailable, unsalable, unsaleable, appealable, available, billable, callable, consolable, controllable, fallible, gullible, incalculable, infallible, inhalable, inviolable, irreconcilable, noncallable, recyclable, resealable, salable, saleable, syllable, unassailable, uncontrollable, unsalable, unsaleable, valable, violable
Unavailable sounds like:
unbelievable, unbelievably, unemployable, unflappable