Upgrading1.5 Pseudo Multiple Blogs (one database) in 2.x?

OK I have a question – way way way way back I set up multiple blogs using the Pytan Multi Blog Hack.

https://www.mutantpop.net/artists/

and examples:
https://www.mutantpop.net/artists/DJNoNo/
https://www.mutantpop.net/artists/Instamatic/

One for each ‘alias’ I release tracks under. It’s using the same database and tables and there’s some custom code in the hack to show a different theme etc. according to which user is logged in (I think, not being a PHP coder – I can see the post database is the same as my 2.6 one, just different userIDs for seperate posts).

Now the person seems to have stopped supporting this, and disappeared, and so I’m left with a 1.5 blog, and no way of upgrading.

Any ideas on how I could upgrade this? I’d like to get to 2.5 or 2.6 for ease of use and security reasons…but unable to in this case as I expect if I upgrade it’ll appear as one blog, rather than multiples.

I could export the posts and install different blogs at URLs but that would be annoying and what I was trying to avoid in the first place.

So is there a ‘user’ plugin or hack to do what I want (just appearing to be seperate with seperate themes would do me, at the different permalinks) or WP MU – that seems like overkill for this.

Oh and I looked at the Virtual Multi Blog but installing symbolic links – WTF? I doubt I have that kind of access or knowledge, in fact I know I don’t. And I don’t want to do domains, just virtual directories/permalinks.