I've done this one a few times, here is the trick:
Step 1: Go to a magical site called Google, enter the following phrase "ski rental (insert out west location here)"
Step 2: Used tabbed browsing, open every applicable looking site
Step 3: Go through and see what each one has, if they don't specify what skis they carry, either call and ask or close that tab and write them off. Sometimes calling helps to give you an idea of what the shop is like
Step 4: Reserve skis
Step 5: When you get there, go as early as possible the night before (usually an hour or so after lifts close) to get your skis, if they don't have what you want in yet, wait a bit, see what appears. Check them out before you leave, make sure they have a decent tune and are in good shape
Step 6: Go back to accommodations, demo/rental skis in hand. Have a few drinks, hit on a few ladies, eat dinner, whatever
Step 7: Get up the next day and rip.
Step 8: (optional) Go back after day on the hill and swap for another pair to try
So I guess I'll summarize in a less smart ass way, yes it is very easy. Search to see whats out there, most places will give you some idea of what they carry. Rentals/Demos are not just available from the resort, check 3rd party places. Get them the night before and have no worries the next day.
Good luck and have fun