I do not drill tanks, but some glass companies will do it.
If you know ahead of time what you want, it is worth the extra $25 per hole to get it drilled.
I am a huge fan of AGA's Megaflow tanks, but it does add extra costs to the tank (well worth it).
The built in skimmer box hides all your piping, and makes the tank more of a showpiece.
I would definitely recommend a drilled tank over doing hang on the back overflows.
You can also hide everything right down to the heater in the sump.
There is nothing better than looking at a tank and just seeing what you want to see without the wires of powerheads, and heaters, etc.
Below is a tank I did. Unfortunately I don't have the before pictures to show how many wires were all over the place, and the mess from the chiller that had been plumbed outside of the stand.
I went as far as putting everything inside the cabinet, including an aquadoser for calcium.
Before I replumbed the tank, it was running on 2 power heads inside the tank, a 950 pump, and a 1200 pump.
Once I was done, it is running only on the 1200 and I had to valve the pump down a bit because of too much flow.
This tank is running a chiller, a U.V sterilizer, a HUGE in sump protein skimmer, and 2 returns
So I guess the answer is a big YES for drilled tanks with sumps.
Hope that helps.
-TheFishGuy