The Secret Designers  

France and Søn Jupiter
Jupiter is a relatively unknown design and not very frequently seen.  As you can see from this catalog photo, the design is not credited to a designer.  It is an in-house design dating to the mid 1960s. 

(The caption)

Yet here is a Mobilia page from 1967, courtesy of Jesgord on this forum, crediting the design to none other than Finn Juhl.  Given the stature of Mobilia, and the great number of design credits that are documented by Mobilia, this is strong proof that Finn Juhl is the secret “in-house” designer of Jupiter.

France and Søn Great Dane Groups, models 127 & 128 and 167 & 168
This is the example that is near and dear to my heart.  Simon (of the Danish-Homestore) has reported on this forum James France’s statement that the Great Dane series was “in-house” ( http://www.designaddict.com/forum/Identification/Grete-Jalk-or-Finn-Juhl).   And here is the France and Søn catalog showing the design uncredited, or “in-house”. 
 
(Great Dane Group models 127 and 128)

(Great Dane Group models 167 & 168)

Here is another France and Søn retailer’s catalog (Povl Dinesen) showing the design tersely credited to “France,” courtesy of Jesgord.

(167 and 168 credited to "France")

(model 168 credited to Grete Jalk)

However, it appears that this is not the whole story.  This catalog from Ønskebo that was an authorized France and Søn representative, which I believe to be slightly later than the France and Søn and Povl Dinesen catalogs, credits the design of 167 & 168 to Grete Jalk.  (Note: look below for a couple of France and Søn advertisements with Ønskebo’s name outlined to prove it was an authorized representative of France and Søn)

And then there is this entry on the Danish Furniture Index, crediting the design of 128 to Grete Jalk, and note that the verification source is Grete Jalk herself via mail.
https://aleph-01.kb.dk/F/XK7XQAY86X82HSBDN9GL3RE3BJEB28NQFKF9S5PHBTNV819M5G-29162?func=full-set-set&set_number=076499&set_entry=000002&format=999

The only conclusion I can find is that the Great Dane group was an “in-house” design and the secret “in-house” designer was Grete Jalk. 
It would be very nice to see further documentation on this point.

P. Jeppesen model 8, a Tea Cart
Here is a tea cart that is credited in this catalog from the mid 1960s to P. Jeppesen for his own company.  We would probably say, on this evidence, that he really is the designer of the piece. 

Yet here is a cart that has been labeled crediting Grete Jalk as the designer.  It is hard to imagine a reason to label the cart as a Grete Jalk design, unless it really is.  The conclusion is that this tea cart was an “in-house” design by Grete Jalk for P. Jeppesen.  

JL Møller, models 55 & 71
This is a notorious example, first pointed out I believe by Howard Moon on this forum. JL Møller documents from the 1950s and into the early 1960s show this design as credited to Arne Hovmand Olsen.