Thanks for the compliments and info. Also, thanks to those that have taken the time to read my build thread.
I still have much reading to do and things to consider. Also, the wife needs convinced, as she says the whole things needs to leave.
Sump wise, I originally had the sump remotely located in my basement in order to keep the display tank nearly silent and house the supporting equipment. I plan on removing it to eliminate a large energy using pump, and to free up some space. Just the sump was about 70 gallons, but I have a small room in the basement dedicated to the support equipment.
With the new layout, I "could" build a new sump. With the space I have available next to the tank, I could build something that would use all of the available space for maximum efficiency. However, it could not be any bigger than 24x24 - 30" tall. Glasscages shows an 80gal cube for about $440. I could build one for less.
I would also be introducing some additional noise into the room. How much i don't know. I am pretty sure I can get the overflow noise down very low, but would still be left with pump noise and any water trickling through the media. How that would compare to a couple of canisters is unknown to me. But it would likely be much easier to work on also.
Also in favor of the sump would be the ability to eliminate the substantial cost of a couple of Fluval Fx6 type canisters. I have a Mag 7 and Mag 5 pumps that I could use, but they may be a little small. Additionally, I could probably get a much better filter for less $$$ building my own.
Sounds like I am tanking myself into a sump.
UG filter wise... I was just thinking with the square footage I have on the bottom of my tank, it would require lots of flow to be effective, and also the accompanying down tubes which I do not like. It seems like over time, the UG filter becomes clogged everywhere except right around the tubes. So eliminating it seems to be the way to simplify things. Mineralized soil looks promising.
Lighting wise, I definitely have zero plans on using halides - sorry for the confusion. I am way behind the curve on current aquarium LED's but I do know that you have to spend lost of $$$ on LED fixtures to come remotely close to replacing 400W metal halides or the the T5 florescent commercial fixtures that I am familiar with. With my canopy, I don't need to spend extra $ just to get a tiny slick looking fixture. Regular florescent fixtures might be hard to beat for my application. What about color shift and bulb life?
I definitely don't want to start an algae farm either.
Now the biggie I had hoped to drastically reduce - water changes. Just speaking for freshwater here... In the past, this has ALWAYS involved a small ladder, many buckets, lots of rock moving and re-aquascaping, and many trips to the toilet, bathtub or other water source, pre-treating the water 5 gallons at a time. I do have the means to keep a 55 gallon drum and pump in my old sump location for preparing the water changes, and if I eliminate the substrate vacuuming, the accompanying re-aquascaping would also be eliminated. So, then I would just be draining water. Definitely an improvement.
However, my ignorance on the subject had allowed me to think that the bio mass of the plants would mostly eliminate the need for water changes. Cycle of life type thing. I feed the fish, they poop, which feeds the plants, which use the nutrients from the water column, thus cleaning it. What about suctioning general debris accumulation from the tank bottom?
I am still thinking of designing my tank sort of backwards. Low maintenance hardware 1st, low maintenance plants next, and then work with whatever fish would be compatible.