I inquired about a month ago for a 30day cruise double price was $1799, single $3500. Agent wanted me to pay brochure single price of like $8000 and then if they found me a cabinmate I'd be rebooked at the double price(which might be higher or lower then it was at the time).
I almost laughed at the guy but hung up instead.
Incidentally I think it is only offered on 2 Hal ships now. You can see which on VTG if you look up ship specs.