Replying to Newschoolers and iPhone/iPod Touch owners... I need your help

So i've been thinking of an idea for a physics based jump calcuating application for like 5 years now.  About a year or so ago I saw an opportunity to design this app for the iPhone and iPod touch and make it mobile so you could use it on site and take advantage of the features like accelerometer, gps (iphone), etc.

Anyway, so I designed the application about 8 months ago and approached a couple of companies to build it. It will cost me around $5000 to get what I want.

This is what the application will do:
It will allow you to answer kinematic based questions jump questions such as
1) How far will I go off x jump given Y perametors
2) how fast do I need to go to clear X jump given Y parameters
4) Airtime
5) jump angle needed given Y parameters
etc.

Parameters such as speed, drag, jump angle, landing height from takeoff, etc. will be used to do the calculations and an angle finder and gps based speedometer will be built in.

So I almost pulled the trigger on getting the app developed but put it on hold indefinitely at the last minute for a couple reasons.
1) There's so many damn apps in the app store now it's hard for good apps to stand out
2) There's no guarantee it would even make the app store given apples frequency of rejecting apps without reason (plus there could be a liability issue even though this will just be an 'educational tool')

So basically I didn't want to gamble with $5g. I don't care if it makes much money, but I would love for it to at least be able to make the app store and break even.

Basically i'm just trying to get a level of interest from NSers and iPhone owners first of all. This doesn't just apply to skiing (any action sport). I'm also trying to figure out a dollar amount for the app. I've been thinking from $5.99 to 14.99, most likely settling at $9.99.