With Beta 4, I had this code that worked fine:
var red, green, blue, alpha: UnsafePointer red = UnsafePointer.alloc(1) green = Unsa
To answer your question about setting the stroke color from a UIColor, this will work:
UIColor
CGContextSetStrokeColorWithColor(myUIColor.CGColor);
I do this a lot in my C++-based Quartz 2D code.