You talking about just a platform or a "shooting shack" as we call them in these parts?
No specific plans to share, but my two cents is to use lumber in dimensions that exceed what you need and to use treated wood (or treat it yourself). The result will last longer, be more impervious to bad weather, and will give you a greater feeling of security when you're a story off the ground. Be sure to brace your pillars or posts with good cross bracing.
You can make them plain or fancy. Some folks I know install a propane heater in the shack, run a copper gas line to the outside, and use a standard propane tank for heat while they hunt. No cold toes for those folks--which would be a big plus in cold Michigan.