That sounds like a really cool conversion, I've never heard of it done before. TLC custom built an FJ45 crew cab and I think they used quite a few tacoma parts, maybe they can help. As far as adapters a concerned I imagine you'll probably need to contact your local fabrication shop.
how about using the engine,tranny,tcase and rear axle from the tacoma? as i doubt adapters are available. you would need to match the gearing to your front axle and need to weld new spring mounts to the axle but i think it would be easier.