Has any one considered using an actual cooler for a Bar top drop in? Something like the picture below, which you can get from Amazon for about $150 (supposedly made out of SS) Minus handles, legs and opener.
Actual drop in ice bins are probably 3-4x more expensive and about half the size.
I can see framing around it and having your countertop (eg. Granite) cut out around the top, maybe add some SS trim for looks (and to hide any silicone/sealant needed so as to prevent water to enter through the gaps between cooler and countertop)
They also usually have threaded drains so coupling to a pipe can easily be done too.
Completely crazy idea?