Just happened upon your question, but your project sounds very similar to ours. We just moved to Houston recently and are building a house north of Conroe. We used Heather Robert at Cornerstone Mortgage Co. in the Woodlands, (281) 367-7005, and were very pleased. I don't know if you're going to find too many places for loans with less than 80% LTV. But you can count the equity in your property towards that number, subject to an appraisal. They'll just wrap your land and construction project up into one loan during construction. We had plans done by an excellent and economical architect over in Tomball. Our builder, the architect, and Heather have done many projects together and the process has been seamless and in our opinion extremely cost effective. Certainly in the affordability range you mentioned and for a high end custom home. If you'd like more info, I'd be happy to share more info. Just email Ken at firstname.lastname@example.org. Best wishes and good luck.