Using LockHTML4 and Anemone, I can place HTML "widgets" on the Lock screen or under the icons on Springboard on my iPhone.
Below is an example of the "Glitchy Boot Logo", converted into a backdrop to Springboard.... take a look! :-)
(If the video does not work, here is a link to my Cloud drive where the file can be downloaded!)
Below is an example of the "classic" Plasma effect behind the icons, and also some "old school" Tracking Sprites on my Lockscreen.
(As before, if the video doesn't work, below is a link)
Let me know if you want some more info on how to make something like this for your (Jailbroken ;-) ) iPhone!