Sure - box stores like Target and Walmart tend to sell new plumbing or major remodel sets, but home improvement stores like Lowees and Home Depot and Ace hardware, and plumbing supply shops and wholesalers, as well as online, you can find lots of individual units.
Course, I imageine if you find a faucet of the type/brand you want, buying it in a faucet/spout/shower head kit is probably no more expensive then just the valve and spout - shower heads are cheap unless high-end finish or ritzy brand.
