For the mini L I have set up right now, I built a relatively large custom stand to accommodate a 20lb CO2 tank and a sump, making it about 3' tall. That also puts it about eye level for me when sitting at my desk, which is nice.
When my 29g was up, I had it on a standard 30" stand, which was about perfect for the tank height and viewing from my bed and across a room, without the light being high enough to get in most anybody's eyes.
I agree with the bigger is better mentality when it comes to tanks, but I'm concerned with weight on a tank that large. A 4' tank is pushing it for me for an apartment dweller, hence the desire to stack. The dimensions are for a tank that is readily available, not too large, and has more depth than standard 55.
I'm also 5'10", don't mind a step ladder as much as too much clutter!
48" seems a bit high to me, speaking just aesthetics-wise, rather than stability. My vote if you want something still relatively tall would be to drop it to like 40". But, I mean, it is all personal taste.
Just for kicks, the left stand is 50" x 24" x 48" and the right is the same at 40", both with the tank dimensions you stated on top. To give an idea of relative size and all.