Hey @griffgreen - great to hear from you! Love what you guys are doing at Slock.it.
We can do such a market for sure. There are basically 2 options you can structure such a market. One would be to name n different outcomes <500k, 500k - 1M, 1M - 2M, 2M - …, >…
The other one would be the numerical market. I created it on the test net: http://test.groupgnosis.com/dapp/#/markets/0x3a0d6f43de2b5f91b2f732a0143b1976/0x1745fc11454fb1507d303d4fee0e4bce83b87f36e
Here you can buy two forms of shares. Long and short shares. Long shares will have the value 1 in the end if the final value is the upper bound or above. Short shares will have the value 1 if the final value is the lower bound or below. Short and Long shares always sum up to the value of 1. If the final value is in between upper and lower bound the value of the shares is proportional. So is lower bound is 0 and upper bound is 10 and the final value is 6: than long shares have a value of 0.6 and short shares have a value of 0.4
For the user it is simple. The market will forecast a number: you will collect 500k ETH and than the user just needs to decide wether they think it will be more or less. If they think it will be more they should buy long shares and vice versa.
We can make a call if you want to start this market to discuss a few more details.
Feel free to create a test account here: test.groupgnosis.com - get some free test Ether here: test.ether.camp and play with the Slock.it market.