I've personally used two XL cases:
Xigmatek Elysium - not exactly convenient hdd tray, bad filtering, but great airflow.
Fractal Define XL R2 - a bit worse airflow, good filtering and very convenient hdd mounts etc.
I don't like the company (often ripping off other designs almost 1 to 1), but I see many dual CPU and multi gpu builds in Thermaltake X series cases. Seems like they offer good value for XL options.