[skrowl]

You might want to start with a web UI then (like SyncThing). This provides you with a simple way to display your data and you get Mac / Linux / etc support for "Free" while also allowing your Windows users to have simple network access.

No extra dependencies, no UI toolkits!

[viktorelofsson]

Yes, and then you have Hadouken (https://github.com/hadouken/hadouken), another BitTorrent client of mine (though server oriented) :)