Do you have any pictures of what you have in mind?
Both ARBReptiles.com and FineGTPs.com have cage plans, although I don't know if FineGTPs has them back on their new site.
Unless you have some plan in mind different from the typical reptile cage, you are basically building a box. Your concerns will be with the size of the enclosure and the doors you'll need for that large of a cage. If anything I would think you'd want to find a plan for a display case and modify it for a snake.
-----
Current snakes:
0.0.1 Gonyosoma oxycephala - Java locale (green)
0.2 Gonyosoma oxycephala - Malaysian locale (green)
1.2 Gonyosoma oxycephala - Java local (green)
2.2 Gonyosoma janseni - Seleyar locale (all black)
1.2 Gonyosoma janseni - Celebes locale (Black & Tan)