That depends on the exact language in the contract you signed. Did it incorporate by reference the blueprint, or did you have the chance to see it, so that your approval was implied? What does your contract say about cancellation, and return of your earnest money? Are you required to make a demand of performance? Give the builder notice of breach and time to cure? Mediate? Arbitrate?
No one can analyze a contract they haven't reviewed, so you need to consult a local real estate lawyer for help.
Avvo doesn't pay us for these responses, and I'm not your lawyer just because I answer this question or respond to any follow-up comments. If you want to hire me, please contact me. Otherwise, please don't expect a further response. We need an actual written agreement to form an attorney-client relationship. I'm only licensed in CA and you shouldn't rely on this answer, since each state has different laws, each situation is fact specific, and it's impossible to evaluate a legal problem without a comprehensive consultation and review of all the facts and documents at issue.
First read your contract documents, and focus on the specifics of what the builder has promised. If the contract documents are typical, the builder will have left itself with a lot of maneuvering room. So, you may have to be creative to prove what the builder reasonably led you to believe that you would receive. Examine the model and other similar homes to yours. You may consider retaining a home inspector to help evaluate what the builder built versus what you were promised.
Even if you find differences, you may still have a problem proving any damages.
Once you document the differences, and what you were promised, then write the builder a letter by certified mail, return receipt requested, to set out your findings and position, and to request the relief that you want. With the economy getting better, the builder may acquiesce.
Also, read your contract to see whether it requires arbitration, and if so, under what conditions. Sometimes, the contract requires arbitration in a remote location or under some inconvenient conditions.
Finally, I recommend that you retain a construction attorney to help evaluate your situation and to provide good advice.