One thing to note: "track specific" threadless stems really don't exist. If you look at what the pros are using, you will see that they are opting for regular road stems with plenty of rise (I assume since most of these riders are using smallish frames and use the rise to compensate). The stems with negative rise are pieces of nostalgia for those who liked the look of older quill stems.

Regardless, there are some who still like and use these negative rise threadless stems, but most are custom jobs. I personally like the look and functionality of some negative rise, but not too much.

For off the shelf stems, the one that comes to mind is the Cinelli Grammo Titanium:



This stem has a 72degree angle (-18 rise) which should put it parallel to the TT. If you are a big guy I would be hestitant to use it because the one bolt clamp is not very convincing. (I have also heard of this stem snapping on people.) It is beautiful to hold and look at, though.

I have one (120mm length). I also have a regular ITM road stem I plan to use with my custom track bike. The frame is currenlty at the paint shop, so I won't get it for another week or so.

If you want to try it out, I can mail it to you to see if you like it. But, mine is for 1" threadless, and I believe your custom frame is 1 1/8".

MSRP: $190-270. On eBay: $60-120.

The other stock threadless stems (like the Nitto posted above) with the classic "track" look have either 0 rise or -10 rise. Might as well get a cheap road stem off eBay with the same rise and save some cash.

Then you have the custom jobs. Bill Holland, Seven Cycles and a few others make custom titanium stem from $275-375. And again others using Chromoly with polished lugs are about the same.

I snagged a custom Seven Cycles titanium stem off eBay for $129. I saw another go for only only $95.



The Seven Cycles stem is for 1 1/8" steerers and has a -17 rise. And was made for 31.8 bars. I am planning to use this stem for another project.

A titanium stem would look real daft with your custom frame. Strong and light. But, even at eBay still very pricey.