Wanted: 1" 700c Carbon Forks with >270mm (alloy?) threaded steerer

For a bamboo bike build, I'm using a Trek 2300 head tube which takes 1" forks. Bamboo is not as light as alu/carbon so I'm looking for some carbon forks to keep the weight down.

Must be 700c and have at least 270mm of 1" steerer showing. I need them threaded, so I guess that means I need an alloy steerer. Also preferably lighter than 500g.

Willing to pay the right money for the right forks!

Firstly, I don't think you can get threaded CF forks with that long a steerer. My 61cm Raleigh Titanium has an 18.25cm headtube which is pretty long compared most TREKs of that era and only took around a 230mm shaft. If you're after 270mm then it suggests your headtube is massive or are you intending to add more threading to it for spacers?
Secondly I'd say don't get an ally steerer (if you can find one anyways) from what i read they are weak and really you're bBetter off paying the sacrifice of the extra weight and get a steel steerer which was more common with threaded CF forks in any case.
For the record my full carbon 1" Mizunos were 430g uncut.

Personally I'd say go threadless, there's loads of 1" headsets out there to choose from, it'll be less hassle and more chance of getting the right fork/bar height.
Bags of luck hunting