I absolutely love the 'Create strip of images' feature and have just recently used it in Xnview 1.97 to join a bunch of photos of my apartment to post an website (home-swap). Fantastic feature in Xnview especially the 'mosaic' setting within it, other softwares don't match it, thank you Pierre.
Ok, here is my feedback of requests;
1) Maybe instead of 'Create strip of images' in English the menu could be better named 'Join images...' or 'Join multiple images...' - I don't know just an opinion especially for when this feature gets reintroduced for MP
2) It would be much nicer if the visible file list pane had drag n drop support; (the file pane in this picture ringed in red)

I know that within the 'Add' dialog, drag n drop is already supported - but I don't really feel I should open another window to do this when a file list pane is already right in front of me. So keep the drag n drop support in 'Add' dialog window but just extend it to the main file list pane too

3) I would love if there was an ability to save profiles of each setting I make. In XnView MP v0.33 I can see that the "Adjust" features can save custom named 'presets' - OK this seems really nice and this should be a part of 'create strip of images' too.
4) It would be nice if a progress bar on the same interface with estimated time was displayed (for larger 'image-joining' operations).
5) Option ability (if possible) to use full transparent background 32bit transparency - especially for when joining transparent images together - this may make the operation of joining images much longer.
6) What about a drop-down menu button on the interface called 'Load last session' in which a list of up to 30 last used file-list sessions can be loaded and re-used again. So the last used file-list that was joined can be recovered. Names could use date naming format in the drop-down menu such as "16-12-2011_001" '002' '_003' etc. If the file/s in the file list are no longer there then on the file list pane, the file/s can be highlighted in red to designate that they no longer exist in that same destination so that when a user clicks 'create' then a small window could display to inform user something like "Some or all files are no longer available to use" - meaning that the file/s would have to be removed from this list.
This 6th request is slightly different from the above 3rd request of 'saving profiles' because saving profiles is for the saving of the configuration settings. This 6th request is for a quick recovery/re-use of the previous file-list when going back into the window again. This is because currently once I press 'create' and create the joined images I may not be happy with the joined result and may want to join them again in a different manner. So rather than going back into the window and manually adding the file-list back again, I could simply click on a drop-down menu button and select and use a 'last used' file-list session.
Excuse me for epic explanation on 6th request, just trying to make it easier to understand.