Yep, but only in Blitz+ V1.39 (latest)...
RequestFile$(title$,exts$[,save][,directory$])
...set the last parameter 'directory$' to the initial path you want the requester to open up.
RequestFile$(title$,exts$[,save][,directory$])
...set the last parameter 'directory$' to the initial path you want the requester to open up.