An opulent table flatpack can be made at a workbench (Bench with vice or better) in the workshop of a player-owned house. This requires 72 Construction, uses 6 mahogany planks, 4 bolts of cloth, 4 gold leaves, 2 marble blocks and gives 3100 experience. The flatpack can then be used on the table hotspot in the Dining room while in building mode. This requires no Construction level and gives no experience.
The cost of making and selling an opulent table flatpack from scratch gives a profit of: -809,860
After completing the hard Fremennik achievements, they can also be traded to Advisor Ghrim in exchange for 117,522 coins being added to your kingdom's coffers in Miscellania. See Flatpack: Miscellania reselling for details.