Well I still think it would be a good idea to do some proper costings and set out the risks/benefits of the Sell or Rent dilemma. If the housing market is as tight as you say then if you can possibly avoid selling off half your LAND (where the intrinsic collateral value lies) then I would take the risk in the short term. I know the numbers are scary, especially when you get to the dreaded 'M' word (milliion) but you should try not to be intimidated by it. YOU are in control, not the money, and with a good business plan and a promise to yourself not to panic into making decisions you will later regret then you'll be fine.
Look at it this way. Try the renting option and if it just doesn't work for whatever reason then you can sell. You can't do it the other way around. Personally, if you've got a prime piece of land in a great location (forget what's built on it) then I'd do everything in my power to hold onto it.