I like the idea of the shaft opening me up too - I'll have to take another look at the inflatable scene. Perhaps it's changed since I bought the inflatable butt plug that wasn't much good.
By the way, the advice I passed on about the 8 inches maximum for anal insertion came from a doctor who'd treated people for torn rectums. Apparently it can be quite dangerous due to the danger of ecoli etc.
I like the idea of two cocks at once btw :-P