Mick Flavin recorded "Longford on My Mind" (written by Longford town's own Mary O'Brien), and Larry Cunningham of Granard recorded "Longford" on his latest album "As Happy As Larry". Also, "My Native Town Drumlish", "Misty Rolling Midlands", and "Where Three Counties Meet" all sing of the lovely county. I don't know if you consider "Lough Gowna" a Longford tune, but if so, Larry also recorded it.
You should stop in at Larry Cunningham's Gym, Main St, Granard, as he is the best living authority I know of, when it comes to Longford Lore. Tell him Bobby said hi :)