Looking Glass is designed by holdemdogg
, and comes packed with HD goodness. You can choose from different Wallpapers for the Home and Lockscreens, includes a full UI replacement, custom loading screens and of course Retina Icons. There are also templates included to assist in the creation of additional icons.
Using GridLock you can place the Icons easily into their appropriate places, without the hassle of iBlank, but you'll need one or the other.