iPad apps I'd like to see...

I have had an iPad now for about 6 weeks. I think. TBI (Time Before iPad) is a little vague. How did I ever stay calm on a flight from Brisbane to Perth before I had this thing?
Wondrous as it is, I thought, when I let my imagination free, I thought that there were still some apps that were missing from the app store:

• etch-a-sketch - no wait, a few people have done that;
• a tunable tuning fork - I showed the middle C tuning fork app to my low-tech acoustic musician friends and when they stopped laughing, their first question was - "how do I change pitch?". It's been done - http://www.apptism.com/apps/stay-in-tune
• OK, how about a Terry Pratchett app - nobody would have thought of that - http://download.cnet.com/Terry-Pratchett-The-Pocket-Essential-Guide-for-iPad/3000-2125_4-75183693.html;
• hmmm - a T-shirt designer? Nah - too many good sketch apps fill this niche;
• a twitcher's diary - really - http://www.appolicious.com/tech/apps/232206-twitcher-edgeware-technology-ltd;
• but does it do aromatherapy - oh seriously - http://www.medlmobile.com/index.php?page=viewapp&appId=5;
• an atlas of tropical skin diseases - eeeuwww - http://www.medlmobile.com/index.php?page=viewapp&appId=5;
• a general aviation flight planner - http://www.medlmobile.com/index.php?page=viewapp&appId=5;
• a 3D polygon modeller - uh-oh, this exercise is starting to get expensive - http://www.lostpencil.com/?page_id=76;

But not EVERYTHING is in the iTunes store - here are some app gapps begging to be filled:

• a trainspotter's diary;
• a patchwork quilt pattern designer.

Knock yourselves out, appers....if I had an iMac, I might try it myself.