being a plumber this idea popped into my head today for stands. use water heater stands with plywood or 4x lumber spanning between the two, or more depending on the length of tank. the stands are fairly cheap(cheaper than in the link if you shop around), extremely light, and easily moveable,stackable, and damn strong! there are also larger ones for the wide tanks.if you like you could even skin it with some stained plywood and throw in some doors for that proffesional look. the only drawback is the 18" heith, but you could set them on blocks to raise it up higher if you like.
http://www.lowes.com/lowes/lkn?action=productDetail&productId=133314-11713-40S22U
http://www.lowes.com/lowes/lkn?action=productDetail&productId=133314-11713-40S22U
