Updated 12 May: This is a modular Egyptian obelisk set that allows you to build dioramas, war game terrain, or whatever else you need a needle-shaped stone column to decorate. I know "capital" is not quite the right term for the part so named, since the pedestal is not a proper column, but it seemed the most likely for a clear description of its purpose.
Update 14 May: If you want a model with more surface detail, check out this file I just found, direct from Makerbot: http://www.thingiverse.com/thing:20271
I may eventually add some hieroglyphics versions to my file, but no guarantees.
Update 24 June: Check out this other obelisk made with 123D catch! http://www.thingiverse.com/thing:96006
All parts connect with a pyramid-shaped projection and socket. there is a small clearance to allow for machine setting variance and, if desired, glue for a more permanent connection. The pedestal, plinth, and capital can be mixed and matched as you see fit for any of the obelisks. The small plinth was designed as a base for the smaller "Obelisk plain" or "Obelisk ornate," but could also be used for the top 2/3 of the tall obelisk. All parts should fit within the height restriction of a standard RepRap, at under 140mm/5.5" without any scaling of the files.
PLEASE NOTE: The "Obelisks" file is only included to show some possible part combinations. Overhangs, total height, and other issues could/will appear.