Newer vehicles weight more, thus the trend of larger brake hardware in order to provide the same or shorter stopping distances. While you may not like or care about the appearance, much of the market does.
My third comment in tongue in cheek.
You may be able to find 16" wheels that fit your truck. Is it the 2008 Silverado in your signature? Tirerack for example lists many 16" wheel choices. Junk yards should also have used OEM wheels that fit.
Since you got what you got,I would not spend much in changing that size unless appearance was your main goal. Tire costs for the same tire in the sizes rhagfo listed are not significantly different enough to justify new wheels.
Edit: Oh, I think I misunderstood. You are looking at replacing your 2008 with a new 2015/16 and 17" are the smallest offered. The brakes on 2015 (maybe starting in 2011?) are larger, thus 16" wheels do not fit.