Isomalt is just one of many sugar alcohols.There is Erythritol,Sorbitol,Mannitol,Maltitol, Xylitol.and Lactitol. In formula they could be used in amounts similar to sugar.But are very expensive as compared to sugar, $1 to $3 a pound. They have a funny side effect called the "laxative effect" if you eat candy containing Mannitol I would be very close to the toilet. The one that has the least laxative effect is Maltitol. The sweet effect in sugar alcohols ranges from 30% to 90% that of sucrose (regular table sugar) depending on type. There has been questions about using Splenda. NO! it is a high potency, non nutritive sweetner, use it in your coffee not sugar work!
Then theres this thing called Intense Sweetners.They are a different colored horse altogether. There is Sucrulose(Splenda), Aspartame(Equal).Also Acesulfame K (Sunette) and Saccharin (Sweet & Low). Pure sucrolose costs about $150 a pound.

Thanks for the info

You're welcome.

OK but there are other types as well.

Sugar for Pouring: Does not have any acid in it.

Isomalt: Theres that stuff agian. I will not elaborate everyone knows what it is by now I hope.

Carbonated Sugar: Put this stuff on a silicone mat in the oven allow it to burn use anyway you want. Yeah I said burn.

Rock Sugar: Pretty good stuff. But I was not impressed with it to much. I have a recipe if anyone wants to try it.

Bubble Sugar: You have to have special mats for this. Not the same as blown sugar bubbles.

Opaque Sugar: made by adding calcium carbonate or titane oxide. You can use paper mache. Mix the above with water and add at soft crack stage (140C). With opaque sugar no need for silica gels and all that other stuff.

Spun Sugar: Just boiled sugar with no acid. I have a recipe. Is some equipment needed though.

Moulding Sugar:You take 2.2 pounds of granulated sugar and one egg white and mix well, you can add color. Make sandcastles and other stuff. I have tried this but did not have to much luck with it still perfecting the recipe.

White Sugar: Add a small amount of blue just past hard crack (155C).It should be noted here that white sugar tends to crystallize very easily.

Information taken from Pastry Chef Consultancy and Information service.
You can find the article that this came out of there.Written by Martin Chiffers just one of the worlds best at sugar art. Would be a great article for those of you who want a little more info. All of this is my wording not the way it was written.