This shop purchased the entire remaining inventory of Precision Scale Castings run of narrow gauge brass cabooses (cabeese?) the two-window cupola model sold out quickly, but Bruce advises the single-window cupola models are still available.
http://www.i-sng.com/1_20_3_Fn3_1_20_3/1_20_3_Rolling_Stock/1_20_3_rolling_stock.html