This is all old news, but it's still quite relevant.
The next installment in the Melty Blood series will hit Japanese arcades in July. Entitled Melty Blood: Actress Again Current Code, it is an upgrade from the current arcade game that will incorporate changes made for last year's PS2 port of Actress Again, including the addition of two new characters, Ryougi Shiki and the seifuku version of Tohno Akiha, as well as numerous tweaks to move properties. Apparently there are further minor changes , but I am unable to read Japanese proficiently enough to list them. Also, as seen in videos from the loketest, the developers have made the attack and heat graphic effects slightly flashier; otherwise the graphics seem untouched from the previous version, which is a little disappointing but unsurprising for this series.
Here's a loketest video showing off the new characters as well as effects:
http://www.youtube.com/watch?v=yggHNqaDKac
Other exciting news is that Current Code will be featured as a tournament at this year's Tougeki Super Battle Opera in Tokyo. It will be interesting to see if the Japanese players use the previously console-only characters in tournament play, as both characters have become relatively popular in the American tournament scene. In any case, Actress Again is a great game and a huge upgrade from Melty Blood: Act Cadenza. I'm glad the series is still going strong.
The official site, which contains the majority of this news:
http://e56.info/mbaaring/