The Alpha 40 Gallon Fresh Water Tank measures 42" length, 23.5" width, and 10" height, fitting well within your specified dimensions for a 2009 Tacoma TRD Off Road with a 5 ft bed. The tank includes an opening at the top for filling with water but is sold blank without pre-installed fittings or spouts. Customers typically install their own connections. For installation, we recommend our Universal Fresh Water Tank Fittings Kit, which contains all necessary fittings and water level sensors. While we do not have a 50 gallon tank with those exact dimensions, the 40 gallon tank should meet your size requirements effectively.