Somewhere on here is a thread where we discussed a measure kinda like what you are looking for. I think it was originally posted on Yahoo, but i could be mistaken.
Anyways, I used SD’s level (with a 70k median income) and todays rates (~5%) that median prices should pivot right around 310k, give or take. Each adjustment to the rate of .25% gave us an 8k swing in the ‘expected’ median. So a 1% increase from 5% to 6% in rates would give us a ~30k decrease in purchasing power, leading to a ‘expected’ 280k median. Most certainly not 210k. No one challenged the math, so either it isnt too far off or I am the ‘special’ kid, dont really know it, and everyone is just being nice to me.(certainly a possibilty)
This is no where near perfect math. RE prices are effected by SOOOO much more than just interest rates that focus on one or two factors can, and has, led many astray. Just because people cant afford it doesnt mean they dont want it, and doesnt mean they wont find a way to get it. (liar loans anyone?)
But if you are looking for a guide post of, ‘what will interest rates do to housing prices?’ I would start there.
(ill let you do the search for it, I dont feel like digging for it)