Bit of advice: http://blog.ycombinator.com/advice-for-early-stage-hardware-startups
You don't need a few dozen prototypes to start, you just need one. A single prototype is enough for any sort of demo. You can build it from an Arduino & a few Cooking-Hacks kits if needed -- main thing is that it should be bare-minimum functional, at least as an MVP. If you're trying to collect data, it should collect that data. If you're designing your own board, build a giant cheap prototype version, use a breadboard, buy some easy-to-solder components, use a toaster oven.
If you need to collect a bunch of data from many different users but don't have the money for a bunch of prototypes (i.e., for machine learning purposes), collect it one user at a time. Until you can afford to build more prototypes at once, there's no reason to build extra copies of MVP hardware that you'll just end up throwing away at the end of the day.
Depending on your budget, 3D print the looks-like prototype at a place like TechShop, or by reaching out to one of the 3D printing shops in your area. If you need an app in association, build the bare minimum app (and you might be able to gloss over some details of the actual communications -- backend interface, etc. -- and simulate data when displaying graphs, for demo purposes -- your prospective investors will know that those parts are pretty well understood already).
If you don't have either hardware or software skills, co-found with someone who does -- you'd hopefully have both on your team, so that you don't need to outsource everything to start. Even if you don't have any EE or ME skills, it doesn't take long to experiment and start building a simple prototype using an Arduino (though depends a bit on what you're looking to build), and you'll pick the understanding up as you go.
There are definitely consultancies around the US that'll help you design something from scratch, on the wearable tech front -- but not too many will work entirely for equity, and it depends on how much funding you've managed to raise. Unless you have a significant chunk of resources to invest personally, or from friends & family, you're probably better off building your first prototype from a bunch of components found online -- Cooking Hacks, Adafruit, SparkFun, etc. (Aren, any thoughts?)