Yeah probally best to open a javawindow. But this can be handled just like the graemlin window works and include the necessary coding from either script we talked about to do it.
I may look at it just like Astaran said he would as well. However other work takes proirity so I guess any us that choose to do get to it then we will.
Now the main part is to write the script which would pull the user's photo's and display the ubbcode like it does on the showphoto.tmpl and then use the post function to carry it over. The javascript is easy. Just replicate the script that pulls the popup window for the graemlinpanel.php script and replace that with the script you create. If get a couple hours to create the scripts I look into creating it I will but its nothing I have not done before that is create custom Photopost scripts.