Don’t know if you are still looking but I’ve been watching ZRX1200 Kawasaki’s lately and they are well on the up. Must be green and mint condition.
If i had the money - this is what id do to one.... http://jamescomptoncustoms.com/ http://jamescomptoncustoms.com/bikes/zrx/
That would be my choice. You've got an 1198 and a Monster so why buy another sports bike (999) or another roadster (Scrambler or 848SF)? An 1100 Hyper would be a different dynamic to what you have now.
Saying that, I'd swap the Monster for an 848 SF. That would be some garage: 1198 SBK, 848 SF and an 1100 Evo Hyper. All bases covered.