Before replacing your curtains as this can be quite expensive for such a large window, if they are in good condition, add a band of extra fabric to the bottom in what ever suits you, your existing curtain track can then be moved up to the ceiling for good looking full length curtains without the large round eyelets, could save you a lot of money, I would look at replacing/removing the sheers cheers

Hi, Pin down a builder? I would suggest you take the plans you have to a builder and get some feedback before you go much further. Builders are often your best ally when it comes to practical ways to achieve the design intent.... many is the time we have been asked to price a set of plans where the client has invested an inordinate amount of time and money on detail only to receive a rude shock when the reality hits the budget for all the detail desired.... cheers

Early Settler has fireclay ones for around $1000.

From Persia(Iran)?!