Cases of gravitational lensing resulting in a recognizable image of an extended object?
There are actually quite a few examples of this. A particularly nice one, where you can see star-forming substructure within the distant, lensed galaxy (the extended, vertical "snake" structure just right of center), is this HST image:



This is another HST-based example, in which the same background galaxy is lensed multiple times (indicated by white ovals) by an intervening galaxy cluster, with a reconstruction of the background galaxy in undistorted form shown in the lower-left:


https://www.space.com/14481-hubble-photo-brightest-galaxy-gravitational-lens.html

People have even obtained spatial resolved spectroscopy within the lensed galaxies, as discussed in this paper (which includes spectroscopy of the first lensed galaxy pictured above).