It's a new concert venue in Glasgow, next to the SECC. It's not quite ready yet, opens in a couple fo weeks I think. I have no idea if it is suitable for Tennis, but I suspect that it would need more notice to be available over a three day weekend.
From the website:
The SSE Hydro is due to open in 2013 and will play host to national and international music mega stars as well as global entertainment and sporting events.
With a seating capacity of 12,000 The SSE Hydro will augment the SECC’s existing facilities, and will play host to around 140 events every year. The SSE Hydro will attract an audience of one million visitors each year, which positions it as the fifth busiest entertainment arena in the world, alongside iconic venues like Madison Square Garden and The O2 arena. From its opening in 2013, The SSE Hydro has the potential to inject an additional £131 million annually into the local economy.