If you choose to construct a home built aircraft, you may do so without an A&P certificate. After successful completion to include inspections, Etc, you will likely be eligible for a Repairman's Certificate. This will allow you to maintain the aircraft that you have built, though no other. The OJT route I believe is still viable however will likely eventually go away. You may work right now under the supervision of a certificated A&P or in a certificated repair station/facility. BTW, Myself, and I'm sure other A&P's, have had offers over the years to accept fairly large amounts of money to sign for someone's experience, which were of course declined. I wouldn't suggest trying to go that route either!