gnome-vfs has the dreaded gnome_vfs_xfer_uri_list() function which has tons of options and offers the equivalent of cp, mv, ln, mkdir and rm at the same time.

GIO offers a much simpler I/O scheduler functionality instead, that lets you schedule a function to be called in a separate thread, or if threads are not available, as an idle in the mainloop. See g_io_scheduler_push_job().