As much as I am a math guy by nature, I don't think numbers *alone* can answer resilience versus stam questions. There are a few things to think about when judging the worth of additional stamina.
First, the damage you can sustain before dying is not a linear function of your total health pool due to healing (and other factors). For example, with 8k total health you can very likely die before you can receive more than 1-2 heals. Your "damage intake until death" might be 10k. But with 12k total health, you are much less susceptible to burst damage and healer mana pool and HPS are the deciding factor. Though your max health is only 50% more, your "damage intake until death" may go up by a factor of 3+. However, boosting your max health from 12k to 14k may not increase your longevity at all if the deciding factor is now your healers' gear (or whether or not they are CC'd, etc.). From this simplified perspective, additional stamina beyond a certain point provides you very little benefit, while the percentage-based reduction from resilience may determine whether your healers can out pace the damage done to you over time.
In short, if you are already confident you cannot be bursted down additional stamina may not be useful. Whether this confidence comes with an attainable amount of stamina is another question
and depends on your class, your team, and what teams you expect to face. For some teams and strategies, you can never have "enough" health.
Second, you should consider abilities that proc off dealing/receiving crits. I'm not an expert on melee classes, but most builds for damage classes invest talent points in effects that depend on crits. By preventing your opponent's crits you not only reduce their damage, but also deny them access to whatever buffs or benefits they would receive.
Being a priest, I know how important our reactive "upon being crit" talents are. We have one very important talent called Blessed Resilience which gives a 60% chance upon being crit to proc a buff that makes us immune to being crit for 6 seconds. With this proc and high resilience, we are capable of chaining "burst damage reduction" with multiple consecutive BR procs off of resilience-mitigated crits. This can give many extra seconds of no burst damage for us our or healing partner to stabilize against the incoming damage when we otherwise would have died. Of course this is a very minor effect, because the talent proc will occur whether or not the crit is mitigated by resilience. But in the case of BR, a proc off a mitigated crit actually makes the effect even stronger.
Anyway, sorry for the long post. If you take anything away from this it should only be that it is extremely difficult to equate the effects of stamina and resilience. Fortunately, except in the cases of enchants and gems, the decision is made for you by lack of diversity in available gear. Personally I will be choosing resilience over stamina when possible because I find it more difficult to find high resilience pieces than high stam pieces. I also feel resilience is more beneficial for priests than for other classes due to BR and because our counter classes (rogues and warriors) are very crit-dependent. So in S2 I will be switching my 12 stam gems for 8 resilience and gem bonuses.