Are there other products than gels that have a high concentration of carb?

Today’s question comes from Francois:I previously asked you about fuelling after running low at Johnsons Crane marathon. So lets say I plan to take in 60g of carbs an hour during runs. This would mean that each hour I would need about 1 Gu (25g) and 500ml Energade (39g). So during a 4 hour marathon I would require 4 energades and 4 Gu’s and if I were to run a 10hr comrades then obviously 10 energades and 10 Gu’s. I am not sure if I can comfortably consume this much fluid and perhaps water additionally. I know that it is beneficial to take in carbs in fluid form, but would you suggest other products that are perhaps more carb concentrated? Thanks, Francois