Kokiafan

I was looking at building a new bike using an Elves frame. But all of the Elves frames I like are using internally routed cables that come up thru the headset and go directly into the integrated handlebars.
I hate those handlebars, as they do not allow me to use my Profile Aero bars from my current bike. This is a deal breaker for me, as I have nerve damage in my hands and wrists and have to regularly rest them on the bars so that I avoid numbness and pain on rides that last longer than a half hour.

So the question for you mechanics: Is it possible to use old style handlebars on a bike like this: ELVES Eglath Pro Disc Road Framesets, all-rounder, Carbon Disc Road Framesets (elvesbike.com)
Where the cables all come up internally through the headset?

veganbikes

I only recommend Gnome frames. In terms of internally routing cables vs not do whatever you want and use whatever bars make you comfortable it should really matter in this situation however I have to imagine with all the hidden cable stuff these days it should be easy enough to find a handlebar that can accommodate aero extensions and the fully internal routing. However I am never really a fan of that, yes it looks clean but can be quite the nightmare to work on. I would look at a different bike entirely personally but I am always leery of unknown stuff.

Iride01 

I'd have to have old style handlebars defined a little better? Most all the different styles are already very old.

Perhaps for any old style bar you are talking about, you just need to drill a hole in it for the cable to go into it and to exit where you wish. Of course if you wish to go into the stem and steerer tube, more drilling might be needed. However if those cables are traditional steel cables and not wires and hydraulic hoses, then tight bends might be an issue.

Kokiafan

Mine are regular aluminum FSA handlebars. The Elves frame has the cables come up through the steerer tube and are supposed to go directly into the handlebars.
I have yet to see a set of these kind of handlbars that are not flat.

Andrew R Stewart 

I would strongly suggest not drilling holes in Al bars. I've been on rides where others have had their handle bars crack and break off due to this more than once. It's interesting to watch a fellow rider do a near perfect side ways flip when beginning to accelerate away from a stop light.

This is right along that "hey guys watch this" type of thing Andy