We generally don't do them in my state because leases 30 years or longer will trigger a property transfer tax. So a transfer tax would be one item to clarify for your state. Also, where do you set up the option periods, and for how many, and how long? Is it a 99 base term lease with 2 options equaling the base term? Regarding commission, they probably will cap the years...so maybe you get paid 6-5-4%, or 6-5-4-3, or 6-5-4-2 (or whatever is negotiated) out to say 20 years. When you get paid is also negotiable - half a leaes execution, half at occupancy, or 100% at occupancy, or some other variation. Obviously, this is not commission you want paid "as collected."
Also, GAAP Accounting Rules may be changing in 2013, which if passed will require companies to report their leases differently than they do today. If it passes, then you will probably see shorter term leases across the board.
Hope that helped a little anyway...