What are my options for quill stems with a big drop, like the Nitto Jaguar?

I'm building up the Pista listed in my sig, and I need a track stem with a 26.0 clamp diameter, or some 25.4 clamp diameter track drops that are made in Italy.

To my knowledge the Jag is the deepest stem available as a quill at 58*, but only comes 25.4. I'm not even sure if threadless stems are available past 15*, however irrelevant that is.

If you need a 26.0, you may be stuck with a Pearl. You could always go Look ergostem, but that would be horrendous on a vintage bianchi build and really expensive, so I apologize for even suggesting it.

I'm sure you'd be in a similar situation regarding price for some Mod 67 cinelli drops etc. I'm not even sure what the clamp is on those anyway.

In conclusion, I have no constructive suggestion to offer.

The frame (which is not yet in my possession) came with a 3T road stem and Cinelli 67-39 bars. I find this strange, since I don't believe 3T ever made a stem with a 26.4 clamp and I'm not sure if the 67-39 was ever made with a 26.0 clamp.

Ideally, I'd like to find either a 3T Pista or Cinelli 2A (or 3A, if it really exists) stem, but I haven't been able to find one in the correct size. I was hoping there was an alternative to using either an Italian road stem or a Nitto track stem, but it's not looking good.

there are some random specialized quill stems (designed by nitto) on ebay sometimes. i've bought two. the ones i've seen don't have the drop of a jaguar, but they are nice. i bought one that's 25.4 and one that's 26.0, both anodized black.

These are nice. Obviously these ones might be a bit out of your price range but sometimes they come up in not as great condition / no badge for cheaper.