Joomla Authentication and member folders

So over at katan website designs, I have a new project to work on ... a website that does auctions and runs classified ads. To do this I decided to use Joomla 2.5 (as joomla 1.5 will no longer be supported from August this year) with wdc auction (still deciding on the classifieds component though). This component allows multiple members to auction their own stuff online. However, one small problem I have with the component was that it did not allow individual members to have their own images directory ... so right now all members have access to each other's files / images ... that's not good ... don't want any issues between members of someone "stealing" someone else's images. So I did three things (so far) ... 1. contact the developers about this issue; 2. installed some other components (JCE Editor and JFUploader) that do allow for the creation of user owned and restricted folders (wanted to see if they could influence the wdc image uploader - they did not, but they did influence the product details part of the add product form) and 3. (just incase) did some research into how to add this functionality - unfortunately I could not find anything directly related to joomla 2.5 or wdc auction ... I could only find two pages both related to authenticating users in joomla 1.5 and one relating to users uploading images to their own unique folders in joomla 1.5. Neither of them offers advice on what files to edit to add this functionality, however.

documentation on authenticating users in Joomla 1.5
Forum thread on how to edit TinyMCE to authenticate joomla 1.5 users and give them their own upload images folder

What's next you ask? Well I think my next step will be to compare joomla 2.5 default login authentication and JCE editor and JFUploader programing code to the code above to see what the differences are.