The next Voca Nico Night will be a big one, as they are planning to run the event non-stop over a 2 day period starting on April 26th. The event will feature over 20 different Vocaloid producers and live bands. The entire cast list is not yet available, and neither is the live stream link, but those will be announced later once they are made available.
The producer and band list so far includes HachiojiP, Samfree, 40mP, Manbou, UtsuP, emon, Kikuo, Sasakure.UK, Tenkomori, Ceasar, Suketch, TEKINA, Nanou, カラスヤサボウ, KEI, PolyphonicBranch and WakaG. Also making a surprise appearance to DJ at this event is SEGA’s own Mikudayo! [Source]
DJ VocaNico Is also returning to perform at this event, and a poll has once again been opened to allow people to submit requests for songs they would like to be played during his session. Suggestion submissions end March 30th at 11:59 PM JST.
Suggestion form: https://secure.nicovideo.jp/form/entry/djvocanico_chokaigi
How to submit your suggestion: http://i.imgur.com/X5nr9F0.png
You can expect the official Voca Nico Night website to be updated with more information as the event approaches.