I've seen an idea similar to this one a few other place (of course I can't remember where
) but your bowl is by far the prettiest! The flowers and colors you used look great!
As far as how long it would last: if you made the bowl thick enough it would probably last at least an hour. Plenty of time to bring out the ice bowl during dessert. Might want to place it on a pretty platter to catch the dripping.