While there are no guides as such, it's a pretty simple process to change the appearance files to make something look like something else.
Lets say swoop to BARC. You'd need to look at the swoop in SIE and see what file it calls, in this case appearance/pv_swoop_bike.sat
Next you do the same for the BARC: appearance/pv_clone_barc_speeder.sat
Extract chain for the Barc and rename the appearance and mesh files files to mirror the swoop, then drop them in your client.
Now when you start your client, swoop should look like a BARC, but only on your client.
Process is pretty much the same for any appearance swap, as long as you make sure you've pulled all the right files.
It'll still be called swoop unless you start changing the name entries in the sting files and drop them in your client too.
