I have made two RMG templates suitable for the recent patches
to make extra-huge maps for Heroes3. These RMG templates are based
on the popular "Jebus cross" RMG template.
While these templates will work with an unpatched HOMM3 (as long as one
selects a two-level XL map), they are best for really huge XXXXL (254x254)
maps, either with or without underground.