Impressive cliffhanger, though I do note that Caster is rewriting his own history to suit his own opinions. He claims that his death was caused because people wanted his money and lands. Nice theory, but at the time of his death he didn't have any money. He had spent it all on his occult research, his mystery play, and his taste for high living. And the only reason he still had lands was because the King forbade him from selling any more of them to pay off his debts.
On another note, there is now a 12 minute OVA entitled Fate/Prototype which appears to be a look at Fate/Stay Night as it was originally envisioned (With, among other things, a female Master summoning a male Arthur as Saber). Be warned, it's designed to look like a trailer (With no guarantee that the actual story will ever be made), so it doesn't make much sense as a self-contained story. The fact that the subtitling is absolutely atrocious doesn't help.
<a href='http://www.animetake.com/fateprototype-ova/' target='_blank' rel='nofollow'>Find it here.</a>