Well, I can't really help you out with any DIY version of the Caddy - I bit the bullet and bought one and will be modding it up for electronic apparatus controls later this year once I settle on the what/where/how I want to go about it. Using it as it is I will say I'm quite satisfied with the unit. Built rugged but still lightweight, stays in place during transit, easy to move/remove (just like the seats), plenty of storage space which is easy and convenient to access when sitting in the shack, has a tight fitting hinged lid with an easy to manipulate latch that keeps it closed when traveling over bouncy terrain. From my perspective it appeared to be a "cry once" product that I personally wasn't likely to build as well and save all that much cash when trying to duplicate what the Caddy accomplishes.
