Don't know if you've ever considered Black Phantoms, rather than the larger fish, but they are lovely and very nice-natured.
I've wanted some for some time - finally have 6 in an empty 15 gal. I'm using as a Q tank right now (they're going in a 35 gal tetra tank and might get a few more down the road) and am even more charmed than expected.
They are relatively tall for their size but quite flat in shape and only one and a half inches max, so can have higher numbers than with the larger fish, unless your heart's set on livebearers.
The males and females look rather different, so it's almost like having two similar types schooling together.
You could, if you liked, get some of these, and a half-dozen or so neons down the road, and make a very nice display, and possibly still have room for a few otos or small cories.
I also have in the Q tank, with the Phantoms, 4 Long Fin White Cloud Mountain Minnows (AKA Meteor Minnows, slender, torpedo-shaped fish, maxing out at an inch and a half also) bought at the same time and destined for a 15 gallon which already has 4 regular WCM, several pygmy cats, (which will eventually be increased to a school of 8 to 10, when I can finally get hold of some more) a male Betta and a very small male guppy/Endler cross, which shows how many smaller fish can go into a smaller but mature, well-planted tank - which is already very active and a real pleasure to watch, whenever anyone's actually visible among the forest within.
(I'm also running both an Aquaclear Mini and a box filter in that 15 g. - snicker at the old-fashioned box filter if you will, but I have the option of running charcoal if I like, I can run 3 filters off one pump, and my betta likes playing in the bubbles.)
There are real advantages to smaller fish for smaller tanks - so much more is possible.
Edit: hi, I'm running for the title of Typo Queen again this coming year, and I feel I have a very good chance of winning.