There are extremes...

What size of frame are you riding?

I'm guessing you could fit a bike somewhere between 60cm and 66cm, depending on a few factors like how low you want your bars.

To a large extent, yes, you can adjust the bike to feel comfortable by raising the bars, longer stem, shorter stem, stem angle, seatpost up/down, longer/shorter cranks, seat forward or back. And, the new threadless stems make it somewhat easier to adjust the stem if you have a new bike with an uncut steer tube. Likewise, larger diameter, longer seatposts are readily available.

I would think there is a limit to the adjustability though. So, you won't do well on a 50cm frame, unless it is designed to be particularly long.