I think a donor hood, a cheap welder, and a whole lot of time... and you could make a cool hood like the one pictured. I think the hardest would be making it perfectly symmetrical.
Matt MSA69 did a vented hood and it came out killer. Wellis is doing something similar w a Viper hood as well. Lots of work if I recall correctly. Another alternative would be to graft in Anvil CF vents...