I'm sorry...
Are you being completely serious? The 4G63 heads are a dime a dozen, you're just not looking in the right places. There are a lot of sites where you can find them.
DSMtuners is one of the biggest DSM communities and they can most definitely point you in the right direction.
The Elantras with the 4G63 engines in it are hybrid swaps... They don't come in stock, but the engines are really similar in size and positioning so its an easy swap. Almost as easy as swapping in a Evo 4G63 into a Mirage.
Howie~
P.S. You'll do fine with the auto tranny, just look into getting a shift kit, and a high stall torque converter. If you're looking to keep yoru car street, 3400 would be a good rating for it. The 7 bolt 4G63 isn't too bad, only 5% of the engines made are subject to the "crankwalk" syndrome, and since you're running a 4G64 block, you dont' really have to worry about it. Might as well look into getting the stroker kit as well.