By 'coin control', you mean the ability to select the coins used when initiating a tx? If so, having a generic UI for this is going to be kind of tough, but implementing policies (randomize, oldest first, etc.) is doable. Being able to broadcast a raw transaction is an hour of my time; setting an arbitrary fee is one line change.

Windows? Most of the low-level APIs have already been abstracted away, but the biggy will be the UI/ncurses. Maybe cygwin has a port for it? Not sure, I would have to investigate.

-M