Maybe you could explain your requirements in more detail? Voltage regulation is pretty simple as there are a ton of fixed voltage and adjustable voltage regulators available. Current regulation is a little more complex, depending on what you actually mean and need. Maximum adjustable current limiting is one thing, adjustable constant current is more complex if that is what you actually require. Generally you have to explain what loads your are trying to power with your panel to understand what you actually require, as load resistance information is needed when talking about constant current modes of regulation. Also the specifications for your panel are needed as far as maximum voltage and max current ratings.
Lefty