Creative uses of a fairly big lot in 78757

[Joshua Merritt]

This is a long shot, but posting to see if any of you real estate pros have any creative ideas for me. 

My wife and I bought in Wooten (basically Anderson Ln. and Burnet Rd. area, in 78757) in 2010, which turned out to be a good time to buy. We love the location, but not really the home. We have way more land than we want or need — it's a 13,262 sq. ft. corner lot that is bigger than the two lots across the street combined. Way too much yard maintenance for a busy family of 5. 

In a perfect world, I'd love to be able to subdivide the lot, build another unit on it, then sell that unit and use the profits to pay off the mortgage on the main home. Then, we'd either borrow the $$ to do a MAJOR renovation or tear it down and build something brand new for ourselves. We'd honestly be perfectly happy turning the entire lot into 2 or 3 townhomes, or a connected duplex or something, and living in one of the units ourselves and selling the other(s). 

But I recognize that is backwards. The bank that holds our mortgage isn't going to let us subdivide, develop, and sell part of the property we currently owe them money on. But we don't have the $$ to pay off the mortgage in advance. It's a small mortgage by central Austin standards — we basically just owe around what the city values the land alone at these days — but we don't have the cash to pay that off. 

Am I looking at this wrong? Am I just crazy? (It's okay to say that I am.) Are there ways to raise the money you need to pay off a mortgage and then subdivide / build several units on your land, with the intention of selling the other units and keeping one for yourself?

How do you go about exploring / financing such an opportunity? Is this the type of project a homeowner can take on with a bank, or are there small investors who can get involved and work out a mutually amicable deal?

Just curious what your thoughts are. I'm sure there isn't much I can do, but wanted to put it to this crowd first. I figure if anyone knows how to make something like this happen (or deem it impossible for once and for all) it would be this crowd. 

Thanks so much for your thoughts. 

-Joshua