I'm looking for something similar to build a travel bike where it's easy to remove the handlebar for packing
Best (only) thing I've come up with so far:
https://www.aliexpress.com/item/1005009161962780.html
This would allow routing cables through the center hole of the handlebars, into the open bottom stem and down the headset and leave plenty of cable for removing the handlebar to place at the side of the frame for packing.
Anyone has a better/neater solution I'd love to know... (other solutions route through the hollow stem, so leaves no slack in the cables when the removing the handlebar)

I think this is the best option if the stem sizes work for you - it looks like they only go up to 100mm.

I ended up getting a handlebar similar to an Aspero 5 bar that lets you route the cables along the underside of the tops then it the stem (FSA ACR stem).  Sadly, I was not able to make the cables route through the stem without causing the whole setup being difficult to turn, so the brake lines are routed under the stem and into the top of the headset.  Since the bar allows for the cables to be routed tight to the underside, that's where I have the couplers.  So not completely concealed, but it's been working great so far.

I run a small Etsy shop on the side

You don't happen to have a link to your Etsy, do you?  I don't know know if you remember, but talked about an adapter you were making for hiding the Zeno couplers under an SMR stem.  (https://chinertown.com/index.php/topic,4455.msg50564.html#msg50564)  Figured I'd see if you sell it instead of having to reinvent the wheel.

We have a first design, and overall it seems to address most of my request.

The only missing piece, and I wanted to ask you, is this

From the drawing, I believe that is the chainstays looking up. In my understanding, the only way they could design that to fit the 42T chainring and the 50C at the same time is by putting a flattened part in the right chainstay. That means that the cable needs to go out around that part, correct? Do you have any ideas or suggestions of how can I avoid this (if at all possible)?

I'm also going through the process of having a Ti frame built by Waltly and asked for internal routing with roughly the same tire clearance, etc.  While you do need to route the cable on the outside to get around the chainrings, those 2 oval cut outs on the chainstay are for the cable to go back into and then out of the chainstay.  There may also be a place on the yoke to tie the cable so things stay in place.

These are Zeno couplers. Unlike the Formula couplers you can put them anywhere along the lines.

I prefer them, but DM me if you want a set of the Formula ones, I have a set I have been meaning to to stick on ebay for a while.

If all you are looking for is a stem that has a routing hole at the bottom, the Pro Superlight might be another option, but I feel like the couplers under that stem wouldnt be very good looking.

Yea the aesthetics are the sticking point for me here.  I'm looking for something that will give easy access to the couplers, but still look good and be relatively inexpensive.

I am curious about those Zeno couplers.  Is that a particular reason you're going with those instead of the Formulas?  Are they small and/or shorter?

I'm trying to find a stem similar to the new Giant SLR Aero stem that has, what is essentially, an open bottom, but for the life of me I can find anything more reasonably priced (they want $300?!).  The channel is used to route internal cables while still making the bike easy to adjust.  My hope is that I can find a stem with a similar channel so I can install some Formula Speedlock hoses to have a travel bike that still has an integrated front end.



Does anyone know of a stem with a similar feature?

This site looks like a good source for headset-specific bearings:

https://www.airevelobearings.com/product-category/headset-bearing-kits/

You could even try the Aspero 5 specific kit since that's what the YFR 068 is a clone of.

Wow, this frame checks off everything I'm looking for.  Also interested if there's a direct vendor selling this.

I hear ya.  If you're set on using a consumer FDM printer, you can design in some holes for metal pins.  Then you'd have some more solid material to take up the preload vs the plastic.

Best of luck!