Oslecamo,

I like your Vampire as a Prestige Class idea. It is very original and it has nice flavor. The idea of spending blood charges to fuel powers is very similar to the mechanic in Vampire: the Masquerade where the vampire has a blood pool and always subtracts 1 blood point from their blood pool each night. The vampire's have special powers that usually require the expenditure of blood points to activate. I had thought of introducing a similar mechanic in my vampire template, but decided against it for now.

Keep up with the Monsters as Prestige Classes, they are very nicely done.