Vallis will keep growing so it would reach the surface and then you could prune it.
Cabomba will grow tall but in m experience, when it gets taller, it doesn't look as nice and also small bits break off very easily and float about the place - it's quite messy.
Amazon swords will grow big if given space and time. I know that you can buy big 'mother plants' off of eBay with about 60 leaves on them and quite tall so they might be good.
I think that's maybe a small wisteria plant that you have already at the front left of your picture. I know they are pretty fast growing so it may be good at the back when it's bigger - I'm not sure how big they get though.
Java fern will grow long leaves but are very slow growing so you would be better to get a large one from the off than buying one to 'grow in.'
These are all very common ones - the more plant-wise guys may come up with something a bit different that would look good in your tank
Hope that helps
Claire