You can see my thread 'Building an Acrylic Tank' in the DIY forum but basically, what I did was I had my local Acrylic supplier cut a 4x8 sheet to my specifications, then I glued it together. BUT MAKE SURE if you do this that you MEASURE the pieces at the place before bringing them home (my guy cut them the wrong sizes).
Costwise it was 155.00 for the sheet cut to "size".
I also bought some scrap for the internal overflow at 2.00 per pound... total... 2.00
Then I drilled the tank for 1" drain, and a 1/2" return bulkhead fittings (The bulkhead fittings were 6.00 each).
Then I built a Durso style standpipe, and return (couple of bucks worth of PVC)
Another thing I realized (other than a better spot for the internal overflow) from doing this was that I liked having the return on the opposite side, or somewhere far away from the overflow because the blast from the return was disrupting the flow of debris into the overflow. So I ended up running the return to the opposite end of the tank (my overflow is in the back/left corner so the return is now on the right rear). If I would have known this in advance, I would have only drilled a bulkhead for the drain, and just ran the return from the sump to the otherside.
There are other alternatives to drilling the bottom as well. If I was going to build another tank and I knew that it would not be viewed from the back, I might consider just drilling the back of the tank instead of the bottom. This way you wont have ANY space taken up in the tank by an overflow box. Just drill the back, place a bulkhead fitting in there, and run plumbing to the sump (you do need a small box around the back of the tank drain to keep fish from getting sucked in there but it would be MUCH less space consuming than the overflow for a bottom drilled tank). However with a back drilled tank you would need to have the tank further from the wall....
But then again your planning on an inwall tank so you wouldnt have to worry about from-the-wall distance.
So for you? I would go with a BACK drilled drain and return on opposite ends of the tank. The drain would go to a sump and biotower, then get pumped back into the tank from the return. This would give MAX in-the-tank realestate, and a neat/clean appearance since all gadgets/etc. would be in the sump.
Building the tank itself isnt that hard...
You MUST get a really clean edge on the acrylic. The edge thats on it after being cut isnt good enough... you need to scrape the blade marks off...
Cementing it is not difficult either, but you have to be careful.... When I did mine, something must have caught my attention, and I missed about 1" with the glue... When I filled it up... LEAK... Then I drained it, cemented that part and so far so good.
You will need at least a centerbrace to keep the tank from bowing out. I put a 12" centerbrace on mine and it still bows a little... NOT in the middle but on each side of the brace about 1/16 of an inch.