Goodness! You combined my two loves, SONIC AND DDR.
I'm loving this. When will the theme be available for download? I'm really anxious to download it!
Oh, and if you need some Sonic songs for Stepmania songs, just PM me.
I'll gladly give you some. ^_^
Oh, and you should find somebody who has a very similar voice to Sonic's VA, and ask that person to say some phrases, so you can have a Sonic announcer!
Edit: About the trailer video, you should probably ask someone who is good with
flash to make a movie for you.