MIDI Studio is a nice solution for people who want a MIDI interface on their iPad, but don't want to fuck around with complicated layouts in TouchOSC/Lemur/TB MIDI. It is also now 60%-off!
For those of you that do like to make your own layouts, that is among the promised features for 2.0. I hate to repeat developer update promises here in connection with promoting apps, especially from unproven developers, but it is a deal at this price so it might be worth snagging while it's on sale.
Here's a demo video from YouTuber SergeyK1985 that shows it off. His English is bad and the video quality is worse, but his music and enthusiasm are great.