Nano tanks in compact spaces
I plan on setting up a nano planted tank of around ~2.6 to 5 gallons as a desktop tank in my dorm. I want a rimless cube style to allow it to have a minimal footprint. So far, I've found Fluval's line of specs, but the V (my ideal size) is a little too big for my desk. I noticed the footprint of the iii is small enough, but I'm a little concerned about the water volume. I am on a budget, so if there are any 5gal cubes in that range, that would be perfect.
The pros of the spec include the integrated sump which I can use as a filter and place to store the heater though. I also plan on upgrading the lights to something like a Finnex Fugeray Planted in order to grow some plants, but this wouldn't fit on the spec iii. I plan on running the tank high-tech, so a light upgrade would be necessary. Any recommendations?
Finally, how can I organize this tank in a compact space? Where can I hide the CO2 tanks? I don't want an extra mess of cords and junk on my desk. If I don't go with a spec, where how can I fit the (hob?) filter and heater and everything in the tank? Space is my #1 concern.