Maikaze "Touhou Anime Project; Musou Kakyou" (舞風「東方アニメプロジェクト・夢想夏郷」), is the title, and Musou Kakyou roughly translates to Visionary Summer District. It's gonna be on sale at Comiket 75, apparently with soundtracks, high-quality prints and postcard sets coming with it's limited edition, price will tentatively be 2800 yen during the event. Also, there's going to be the ability to get a reproduced script that's been signed by the awesome seiyuu list. The doujin group will be located at West hall 2, on day 2 (12/29), section あ (hiragana A) block 41A.

The list is as follows:

Hakurei Reimu: Nakahara Mai
Kirisame Marisa: Sawashiro Miyuki
Shameimaru Aya: Fujimura Ayumi
Patchouli Knowledge: Takahashi Mikako
Izayoi Sakuya: Tanaka Rie
Remilia Scarlet: Tsuji Ayumi
Ibuki Suika: Toyosaki Aki
Narration: Inoue Kikuko

I'm so excited if this shit is happening, since holy shit this cast list is insane. I'm not too happy about Reimu, but jesus christ Suika, Remi, Sakuya, Patchouli, Aya, all of them! GENIUS!

Among these groups there's one specific group that receives a lot of attention due to their flash animated music videos accompanying every CD release, namely IOSYS. With a core group of members, IOSYS releases at least one CD with Touhou doujin-music every ComiKet, and they are usually accompanied by other artists from other Touhou fanprojects, or just buddies of the IOSYS crew. At C73 however, there appeared a new group being promoted using the IOSYS website.

I am of course talking about ALBATROSICKS, the brand new group that has spawned off IOSYS. Having spawned from IOSYS, ALBATROSICKS includes faces known to fans of IOSYS such as Dr.ARM, quim_underconstruction↓, Countess YOUNO and Master Joe. They have added in a final member who has been present on various IOSYS CDs, aswell as being host to one of the podcast radio shows on iosysos.com, miko+Ressurection. They describe themselves thusly:

「アルバトロシクス」とは、イオシス発のキラキラ系エレクトロ・ポップ・ミュージックユニットです。
miko、ARM、quim、夕野ヨシミ、カギの5人をクルー（メンバー）に据え、音楽制作・CD販売・ライブ出演などの活動を行います。

Attempted translation:

ALBATROSICKS is a sparkling music unit, spawned from IOSYS, which aims to create electronic pop music.
With miko, ARM, quim, 夕野ヨシミ and カギ as the founding five members, we intend, among other things, to produce music videoes, release CDs and hold live concerts.

Having acquired their new CD and thoroughly listened to it, I would consider it very good and one gets the feeling that they have tried to mix in the old IOSYS-style music from ARM with attempts at other genres, especially with the last track on the CD, マンボウの中心で、愛を歌う. They are a bit overpowered though, as they have gathered all the most reveled talents from IOSYS into one group. With YOUNO providing excellent lyrics, ARM with his ever-so-great music, accompanied by quim's mixing of their vocoder and providing backup vocals, together with miko's brilliant voice that keeps getting better the more she sings and lastly, Master Joe and his famous flash animations and designs providing the graphical profile for the whole group, they have started off with a boom on C73, held their first concert and gathered a huge fanbase already.

I highly recommend checking their CD out if you like electronic pop music that matches the style of IOSYS. Demos of some of their songs are available on their blog. There's also the music video of the song ストロベリーラブジェネレイター available for viewing on the site.