I found this inspiring post on do-it-yourself windows – I found it inspiring because it shows how far you can get on your own with only basic carpentry skills. The price from a professional craftsman was $5500 but in the end they were built in 4 days using $540 worth of materials!
Though I am wondering though if (1) this approach can be scaled up to a larger home and (2) if, with a reasonable investment in time and materials, it is possible to create longer-lasting and energy-efficient windows?