For ICS 4.0.4 here is two mods battery percentage(circle and rectangular);instructions:
copy systemUI in system/app with permision RW-R-R and then reboot.
Your phone must be rooted.
PS:systemUI is for circle and systemUI(R) is for rectangular;if use rectangular delete(R) the files must be systemUI.
UPDATE:new mod named android is systemui(A)
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