Answering my own email :)

"njsf" == Nelson Ferreira <nelson.ferreira@verizon.net> writes:

    njsf> Hi all, I did some searching on the info for Gnus and the
    njsf> reference about mode lines that I found only spoke about
    njsf> chopping Gnus contribution to it by setting
    njsf> gnus-mode-non-string-length.

Ok, so in addition to this I found the following:

;-------------------
; gnus-article-mode-line-format
;   User Option: *The format specification for the article mode line.
; gnus-category-mode-line-format
;   Variable: The format specification for the category mode line.
; gnus-group-mode-line-format
;   User Option: *The format specification for the group mode line.
; gnus-server-mode-line-format
;   User Option: The format specification for the server mode line.
; gnus-summary-mode-line-format
;   User Option: *The format specification for the summary mode line.
;-------------------


[...]

I am also attaching a patch to allow customizing of all Gnus related
major and minor modes for any interested. 

Best regards,

     Nelson