I realize, in theory, that there are always smallish players who defy the prototype size qualifications and still become good, or even great players, but the % chance of them doing it is always less. Since they are giving up size and strength, they have to be really, REALLY good.
I tend to avoid these players for this reason... unless they slide into a draft round where you can take that chance.
One guy I have on this list is Chris Rumph ii, from Duke. He's clearly too light... and I wouldn't invest a high pick, but if he slides into the third day, I might take a stab.