Thanks very much to cbwmn, I now have a huge amount of plants in my 55. Here's the before shot:

This is actually before I added some moneywort and another similar plant, but here's what it looks like now (temporarily, until I re-arrange)

As you can see, I now have a truly heavily planted tank. not all of these will remain in this tank, I am working on re-sealing a 37 gallon and many of these will probably go in that one, but I will probably plant them all in groups and then thin out the groups.
As you can see from the first pic, I have about a half-dozen swords that have been in place for a while. The larger swords in the center probably need a little more space, the one in the rear is within a few inches of the back glass, but does fine. I am wondering what the proper spacing should be for maximum plant health. I will probably be removing all of the Vallisneria on the left side and put that in my 10g fry tank, just because I'm pretty much tired of dealing with it, it grows so frakkin fast. Someone suggested at one point that I let it grow across the back of the tank, maybe I'll do that, but then I'll have to move the swords, and I'm hesitant to do that, but whatever needs to be done.
It's late and I have a huge garage sale to run for the next 3 days, but here's the list of plants that I just got:
8 12” to 15” Stems - Ludwigia Repens
6 12”-24” Stems - Limnophila sessiliflora
8 10”-24” Stems - Hygrophila polysperma 'Rosanervig'
3 10”-12” Alternanthera Reineckii “Rossaefolia”
8 10”-18” Rotala Rotundiflora
Aprox 12 Dwarf Sag
And existing ones are:
6 swords, can't remember exactly what
6 red temple
40+ Vallisneria nana
12+ moneywort (some struggling)
6 something like moneywort but red, can't remember
1 crypt wendtii florida sunset recovering from massive meltdown.
Substrate standard aquarium gravel, lighting 2x32w T8 6500K Max Plant Growth, ferts 2x weekly Flourish Comp, Excel, Potassium, & Iron as needed, and Root tabs but need to do those again after re-arranging.
Fish are community, about 38: mollies, guppies, platies, swords, tetras,
SAE, red tail shark, rasbora, neons.
Any advice or suggestions appreciated!