Well, now you can compliment those themes with matching skins for the standard Windows Phone lock screen, thanks to Wajk from XDA. The "HoneyLock 3.0" skin is shown above and "GingerLock 2.3" is posted below.
If you're looking to switch up your lock screen graphics a bit, head over to XDA-developers and grab the proper CAB files and wallpapers (currently for WVGA only). Please keep in mind that these modifications are for the default 6.5 lock screen, so applying them to unsupported lock screen styles, such as the one found on the HD Mini, will likely cause issues.
Note: it's always a good idea to backup your lock screen files before modifying them - just in case