Maybe the Waversa Wstreamer Streaming-Bridge could fit your needs as well although it is a little cheaper than the other mentioned solutions.
(There are bigger and more sophisticated products by Waversa like the “Wrouter”. But unfortunately this doesn’t fit the criteria as they have optional SSD slots. But the Wstreamer Streaming-Bridge does not have it and is only a bridge.)
Interesting little transport.
Certainly a Sonore competitor.
Is it even possible to spend that much on a DAC?
I readily concede it could appear a bit lewd to some.
HI Thomas,
The 3 I recall are your first two plus the Antipodes EX.
Best regards, BF
Putting morals, motivations and concerns about lewd behaviour to one side, what I’m meaning is, does such a device even exist?
There are many.
Check the price of the MSB Select DAC II, with 2 power supplies 
Sonore, but then I’m a fanboy. Running an opticalRendu Roon lite version with a Sonore Power Supply (Shunyata Venom NR10 power cable, SR black fuse, and Ghent Neotech 16AWG solid JSSG dc cable, Shunyata Venom USB cable) into a DAC V1, preceded by a pair of opticalModules, and I never thought the V1 could sound so good. In the office a microRendu 1.4 into a Matrix Mini-i Pro 3. Solid stuff. The Signature’s probably that much better, but certainly at a cost. I will agree the Signature is ugly, but it does take care of the mess that can ensue with separate ps, etc.
OMG … £84,500 !
A lot of deep pocketed folks who experiment with different things and listen to a lot of options seem to place the Taiko Audio SGM-Extreme mentioned above at the top of the pile!
Innuos Zenith Mk3 (£3k) or an Innuos Statement would do the job (£10k) both of these can act as a Roon endpoint or Roon Core device and do not have an in built DAC.
None of these fit the discripion.
As said above, the goal is to partner a “transport only” with a DAC.
Not a file server.
The Innuos products have a different purpose.
As explained on the thread’s title and description, the goal is a “silent” transport, acting as Roon Endpoint. Not a server.
The candidates remain :
This is a server.
Just like the much cheaper Innuos, it doesn’t fit the description.
Thanks anyway 
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Before posting, PLEASE READ the thread title and description
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Thomas,
The Antipodes EX is designed to be an ultimate Roon endpoint but can also limp along as a low grade Roon Core.
Best, BF
I forgot to mention the Lindemann Limetree Bridge. (Unfortunately no USB output, but Roon Ready.)
Oh okay - but you could also look at it as a computer with SQ-optimized components - you could have it configured any way you wish!
How about an Auralic Aries G2.1 ?
I’ve got an Aries G2.1 and it’s great but the OP considers it has surplus functionality as it can use optional internal storage and so become a server/player. As a Roon endpoint, the internal storage shouldn’t be used.
No one reads the thread’s description, not even its title 