Ah..., it does appear like you have to unlock your wallet if it is encrypted to stake... Is there a way around this, otherwise a button in qt might not be a bad addition? Although, I guess you can still go to the console and change it.
you MUST have your wallet unlocked if it is encrypted to stake. this is true for all PoS coins. this is because it needs to use your private encryption key (the key you use to unlock) to create the staking transactions.
im confused on the second part of your post. a qt button to do what exactly? unlock the wallet? or start staking?
A Qt button that unlocks the wallet (so you don't have to open the console), when pressed it would prompt you for your password and then ask for how long you'd like to stake. Also, this might be work than it's worth, but is it possible to make the minimum stake time vary based on time since last transaction (like difficulty)?