my ciao is a bit on the extreme side, but you can read about it at <mopedwhorehouse.com> if you want to.
if i were to build another mild ciao (which i want to do) i would probably go with a malossi 50cc kit, 1313 dellorto, no variator, proma circuit pipe (or polini top one, as the proma pipe cant' be found anymore), milled head, cut crank and opened up the intake to be 13mm.
all of that with a slightly smaller rear pully should give you about the same take off as a stock ciao (nothing spectacular, more like a stock 1 speed puch), but a pretty awesome mid range and top end.
you could spice that up a little with a variated transmission, malossi variator and the malossi gears, but then you're looking at a lot more money for better acceleration and probably 5mph on the top.