Many places, how far are you from Chico Cali?? Sorry don't know the area but Josh at Chico Race Works can make you anything you want for the mr2. In my area I have a great fab guy named Rob, flipsidecustoms.com or I have the other option of Casey at Speedware. Get out there and meet some of the people that work on performance cars in your area.
The thing about custom brackets vs recaro or other brands is "Peace" of mind. I've seen some brackets that are too thin, and have failed in a crash first hand. So when the time comes I would feel much safer that the brackets that hold my seats in are made to my specs using high grade materials, and fitted properly not a one size fits all type of job. That's me but to each their own. I mean you trust your life to so little in cars and considering the velocity it's something to think about.