I have an insulated CFS bag - they are really nice - it comes with a jel pack but if it is super hot you might want to add more...it is 3 ' long and triangle shaped to match your kayak...here is the link
http://www.creativefeathers.com/KayakFishBags.cfm
and one of it's main features was named after you >>>>> LOW PROFILE
Because of the Pie Shaped design, it will fit most kayaks, and because of the folded sides, its LOW PROFILE.