I actually have a pretty similar build that I've had a considerable amount of success with. You can see it at: http://deckbox.org/sets/279257 - note that the SB is still up in the air, but rest of the deck is pretty solid.
The biggest differences I'm seeing between our builds is in the removal. It might seem absurd to be running 15 pieces of burn/removal, but I've actually found it to be quite effective in maintaining control of the board (especially with Blood Artists having their fun).
Aside from that, Rakish Heir might be good in increasing the size of your creatures, but it doesn't really help out much beyond that. At the three drop you really want to be making a stronger play, whether that be a Stromkirk Captain or a Vampire Nighthawk. Similarly, I can see where Vampire Nocturnus could be huge, but on the other hand, I can also realistically see where he's telegraphing your plays to the opponent in exchange for the bonus.
Third, I know there's a considerable appeal behind Exquisite Blood, but you're better playing 2-3 cards for 5 mana than playing just one enchantment that doesn't even guarantee any effect. I would actually suggest dropping them for some Sign in Bloods to help replenish your hand (and at the cost of one nighthawk hit).
Lastly, I can see where both our decks would benefit from Falkenrath Aristocrats, but speaking at least for myself, I don't know that the deck is strong enough as a whole to really justify dropping the cash on them.
Anyway, I hope some of this can be useful. Good luck!