No, because residence time, diameter and air volume all have effects on skimmer operation. Increasing the skimmer height increases the contact time, whereas the skimmer diameter controls the bombardment rate (which is the number of times a parcel of water bumps into a bubble... in a sense, bubble density). The bombardment rate is ultimately the the limiting factor to how much a skimmer pulls out of the water column. If you had a super wide body to the skimmer you'll just have a bunch of bubbles in the center and not much else going on. You need the narrow diameter to create the bubble storm of death that we use in our skimmers to get effective contact between the bubbles and water.

The airflow rate is determined as a function of skimmer diameter, length, bombardment rate and absolute contact time, which are all functions of the amount of water flow through the unit itself. So when you are designing a skimmer, you select a throughput rate (which is specified as a function of the tank volume you are trying to skim) and then you design the other parameters around this. And to complicate all of this, how you design all of those parameters depends on what bubble contact pattern you are using, what type of air injection your are using, whether you shred the bubbles, etc... There is a definite optimal zone for parameters.

i saw a guy on kijiji selling a diy skimmer made out of one of those blue 5 gallon water jugs.