I had a project where we thought about doing it. In the end we did a lot of the things that would go towards LEED certification, but didn't actually apply for the certification. Between the cost of what you have to pay USGBC in fees and the expenses involved in our preparing and submitting the documentation, it gets to be a decent amount of money. The client decided to use those funds towards tangible enhancements (i.e. it provided us the budget to install a cistern system for irrigation).

fuck LEED

The new LEED for homes has a process for LEED for existing or new homes that you renovate. It is really hard unless you are gutting and starting over. A lot of things that get you points like solar orientation are not available on a renovation. You need to do energy star lights, appliances insulate everything, etc etc. Some of the points can be difficult with an existing building, like the insulation, (try that with a solid wythe brick house) and no wood framing members in contact with cement. We just did a LEED certified renovation of a multi family project, under the commercial LEED and are in the process of LEED for homes on a bunch of renovations of houses for sale in a low income neighborhood, so it is possible, but expensive.

How much does it cost to file and then certify it or whatever they call it in LEED-ese?

And for an school 2 or 3 wythe solid masonry construction, your studs really cannot touch the exterior walls?

If you are a non member of USGBC it costs about $500 in fees to do a single family house. The real expense is in preparing all the documentations that you have to send in. Its not something that can really be done by a draftsman or admin assistant. We estimated at a minimum 50 hours of billable hours X a project architect's rate ($100-$150 hr depending where you are).