We had something similar a couple of weeks ago. S got a vomity bug in the middle of the night, spent all night fairly low (I even reduced the basal on the pump) and ketones were the last thing on my mind as she was never above 6.2. I phoned the hospital team for advice about 7am and they asked whether she had ketones, and she did, although only at 1.5 or so. They told me to come in etc etc.
Basically it turned out they were starvation ketones, and as such normal and to be expected having not eaten since mid afternoon in effect. She was on a drip for a few hours and began to be able to keep down water/squash. Ketones remained hovering around the 1.0 to 1.5 mark until she had some dry cereal the next day, after which they disappeared quickly.
I was all set to therefore ignore ketones with low blood sugar until a GP friend of mine said that you can have DKA with low blood sugars. Only a hospital blood test will be able to tell the difference, so it is worth checking them out. However if they are just starvation ketones it is possible to relax a bit.
Full sugar coke is great - I think the caffeine helps a bit too - as are dry rice crispies. I can imagine passing off blackcurrant flavour dioralyte rehydration sachets as "special ribena" at a push, but when children are ill they just want comfortingly familiar food rather than anything new. I think that once they can keep something down let them eat what they fancy. I always go back to my mum's remedy of mashed bananas and then cream crackers with a little marmite/bovril/vegemite spread on when I am ill, but no-one else in the family likes that solution.
I hope Khaleb is feeling better now,
Mary