Some yes and some no
Change username, username colour, glowing username can all be done ( see the new items posts )
as for the pictures you can have whatever images you want displayed in the shop but depending on what you want it to do depends on what item the image was for i.e if you want a monkey that has no pupose other than to look good in someones inventory then use a mokey image for rock item and change the name to monkey. If you wanted the monkey to show in a users profile next to their posts you would have to add the 'flag' mod and upload a monkey image to the appropriate folder.
New items are always being created and there is even a very good tutorial on how to create your own by Basilbeard so you should have a look there as i did and created my own Karma bash item (used to knock Karma off other members) which was my first ever attempt at any sort of code writting.
