If you want to create project with a Maven archetype you type
mvn archetype:generate -DarchetypeGroupId=... -DarchetypeArtifactId=... \
-DarchetypeVersion=... -DgroupId=... -DartifactId=... \
-Dversion=...
How this line would change if you are using Ivy?
ivy is not a drop in replacement for maven, it's a dependency manager for ant. If you want to use archetypes ivy won't be of any help
Since Ant + Ivy is all about configuration and flexibility, since this combo doesn't rely on conventions, since it doesn't suggest any methodology or structure, what should a "default" Ant + Ivy project looks like? Does this question even make sense?
You'll find some template for an empty project (like this ivy-template) though.