You would be quite surprised at the number of gated communities within the Denver metro area. Most are single family homes, but some are patio homes or townhomes. This list only includes neighborhoods that are gated, not those individual acreage properties with a gate at their entry. If you are looking for a property like that, let me know, I can find it!
I have listed them by the City they are located in -
Reunion (homes backing to golf course)
Cherry Creek Vista (just the larger homes)
There is a section of Roxborough that is gated also.