Hi kalon.
I had a look through the Play Store and also didn't find a lockscreen app that does quite what you want.
The only thing I can think of is to attach text directly onto your lockscreen wallpaper with an image editor such as PhotoShop, Gimp (it's free) or one of several online ones (also free.) If you need any help doing this, just give me a holler here. I'm guessing from your post that this isn't quite what you want either, but it's all I can come up with for you.
And who knows - Maybe someone else will come along with a better idea.