We've seen a few types of island bases over the years through Shattered Temple, Metropolis, and this beauty made by another mapper a year ago: http://www.teamliquid.net/forum/sc2-maps/503494-2-sma-karōshi
I know there are more maps but these are just quick examples.
I do wonder though if island bases are still possible, or if the race design simply doesn't support the play style. With a current map i'm working on, I have two different ways of doing islands, as seen below:
Both have a twist, or an added value, but I do know at the end of the day they either won't be taken, or they will be abused. In the second image, the base is a temporary island until the gold base is mined out or until the rocks are destroyed.
So, I have to ask, as a mapmaker who wants to play around with island bases more often, what are your thoughts on island bases in general? Do you see a way they could work? Would it be more resources? Would a watch tower on an island be sufficient? Would island bases near the middle of the map be better? Or are island bases simply never going to work?
If you have ideas as to how they could possibly work, please share your ideas.