Even the smaller problem is not tractable, if we are to examine all possible combinations. Let's assume that you have access to a petaflop speed machine, and it takes 10 floating point operations to characterize a single combination. That means we could generate 10^14 combinations in one second. Using Ramanujan's approximation for log n!, I get something like 10^2106 years to generate all possible 900 record subsets. So let's not look at all possibles, it is just too daunting.
Instead, let's see how many subsets we would have to look at to have a 50% chance of finding one that has at least 5 equal values. First, using a hypergeometric distribution, the probability that any single subset of 900 has at least 5 equal values is 4.13*10^-9. Now we consider a geometric distribution, apply some approximations, and see that we need to generate about 121 million successive subsets to have a roughly 50% chance of finding one that has at least five equal values. That might be doable in SAS in a reasonable amount of time
The original problem is still intractable. The probability of at least 5 equal values in this situation is on the order of 10^-40, so we are looking at about 2.6*10^40 subsets to have a roughly 50% chance of finding one. On the petaflop machine, this is still 10^25 seconds or 3.2*10^17 years.