An Mahogany cape rack flatpack can be made at a workbench (Bench with vice or better) in the workshop of a player-owned house. Like when making the normal Mahogany cape rack, this requires 72 Construction, uses 4 mahogany planks and gives 560 experience. The flatpack can then be used on a cape rack hotspot in a Costume room, either in building mode or not. This requires no Construction level and gives no experience.
The cost of making and selling a Mahogany cape rack flatpack from scratch gives a profit of: -6,590
After completing the hard Fremennik Tasks, they can also be traded to Advisor Ghrim in exchange for 675 coins being added to your kingdom's coffers in Miscellania. See Flatpack: Miscellania reselling for details.
See Cape rack for a list of capes that can be stored.