Hyde, is that a paint roller tray?
'lakester, 14" drop base aircleaners can be good in situations like yours. You can have alot of drop and still have good flow, the linkage arm will probably determine how low you can go (limbo music). I used to use one, the raised center section fit within the scoop but the outer edge was just too big to fit within the scoop and would nearly touch the edges, it was tempting to modify the outer edges by squashing them inward a bit. There are also some offset bases available:
http://www.pitstopusa.com/detail.aspx?ID=55371