You could always build a Turbaque.
If that's a bit much, there is always the humble half-million BTU weed burner from the local big box hardware store.
Seriously, if you want to entertain and sear a bunch of steaks all at once, it's hard to beat the 36" Blackstone griddle.
I have one, it's fantastic. Great cooktop, very even heating, rolls like a dream. The possibilities of what else you can do with it are endless. Do not get the 2-burner, it is designed very poorly, it uses round stove burners that only heat up a tiny area of the griddle and the tops on the 2-burner are prone to warping.
You could also go with a propane turkey fryer and a big Lodge cast iron pan. I have two of these... At 50k BTU, they will get that pan insanely hot in short order.
As for the TS8000 and a searzall, they are a great combo and you could use an adapter hose to run it from your 30lb tank. The searzall does a great job, but, unfortunately, it is not the most expedient way to sear.