Part 1: Media Post
Well guys, here's part of my own little Nodame Festival for you! I've attempted to round up all the "bonus features" for Nodame Cantabile I could find. I'm afraid that I didn't have many resources for subs but there are a few subbed cast appearances!
Behind the Scenes Specials (both unsubbed)
BtS SP for the Series [44 min, 640 MB] In seven parts @ Mediafire
(Uploaded by topazera)
Introduces the series with a good amount of footage from the show. It has short interviews with the all the actors talking about their characters (though there's also more of Ueno Juri and Tamaki Hiroshi), footage of the Nodame Orchestra performing and filming the gag scenes and some behind the scenes. In particular: at 23:10 there's footage of Ueno Juri practicing her piano and right after that Tamaki Hiroshi conducting which was very cool! Also, there's apparently a Nodame Café in Harajuku? And they show the real music school they filmed at. Without subs, it's probably more of a watch for hard-core Nodame fans. ;)
BtS SP for the Special [Total: 41 min, 910 MB] Parts 1, 2, & 3 @ Mediafire
(Uploaded by topazera)
SPOILERY for the second part of the Special, if you haven't seen it!
Part 1 - Behind the scenes footage, especially the cosplayers coming off the train and lots of them throwing the doll that looks like Nodame for the gag shots! Very cute.
Part 2 - More BtS footage: the halls used for Chiaki's conducting competition, the Conservatory of Paris where Nodame goes to school and the use of super-powered wind machines.
Part 3 - Tamaki with a towel on his head, an adorable story in English by the conductor who plays Viera-sensei, one of the awesome castles they filmed in and Ueno Juri doing some stuntwork! This special is pretty awesome even without the subs. :)
NG Scenes from the SP only 2 min @ Daily Motion
Series DVD Extras (all unsubbed)
(Files now mirrored by me on mediafire, from this post @ the_s_orchestra by moonymoo.)
1) Behind the Scenes [Length- 07:16] @ Mediafire
Fun to watch even unsubbed! It shows the shooting of cracky 'gag' hitting scenes from the first two eps. Features Tamaki Hiroshi making hilarious faces and being concerned after he smacks Ueno Juri. And lots of Tamaki, Ueno Juri and Harisen. ♥
2) Juri's interview [Length- 22:05] Embedded vids from DailyMotion @ Nodame Cantabile Resources blog, unfortunately no translation.
3) Tamaki's interview [Length- 14:22] Embed vids from DailyMotion @ Nodame Cantabile Resources blog plus a summary sort of translation for the first part.
4) NG scenes [Length- 14:54] I could only locate a clip from some awards thing, @ Mediafire.
5) Nodame Orchestra + Juri & Tamaki [Length- 06:06] @ Mediafire
A short interview as they introduce the Nodame Orchestra, not particularly exciting if you don't understand Japanese but the minute at the end is adorable. Tamaki is conducting along backstage with Ueno Juri dancing along next to him.
6) Wrap up [Length- 06:54] @ Mediafire
Behind the scenes of shooting, interviews and the actors' goodbyes after filming their final scenes. There are hugs and tears, which are both adorable!
Appearances (some subbed, some unsubbed)
Ueno Juri, Tamaki Hiroshi, Eita, Mizukawa Asami (Kiyora), Koide Keisuke (Masumi) & Takenaka Naoto (Strezemann/Milch) on Waratte Iitomo! Autumn SP 2006.09.06
Unsubbed but go here for both a detailed summary!
On mediafire: Intro, Parts 1-4 & Translation Summary txt file
I recommend you read the first four paragraphs before watching the intro, part 1 & part 2. BUT I would watch parts 3 & 4 BEFORE reading their summaries so you don't spoil the end of the game! This appearance is just adorable, the cast seems to get along so well and there are several hilarious and surprising moments. If you watch nothing else, I highly recommend you check out this one! ♥
Ueno Juri and Tamaki Hiroshi on the game show Waratte Iitomo! 2006.09.16 (subbed) 4 min on Daily Motion.
Adorable, adorable, adorable! They're too cute and Juri-chan ruins everything. ♥
Ueno Juri and Tamaki Hiroshi on Bistro SMAP, from SMAPxSMAP 2006.12.04
Subbed (on Daily Motion): Part 1 Part 2 Part 3
Unsubbed (HQ download): Seven parts @ Mediafire
PLUS, a detailed summary with caps!
The members of SMAP cooking a meal for Ueno Juri and Tamaki Hiroshi! It's just as charming as it sounds! You get an idea of how both of them have certain similarities with their characters. :)
Ueno Juri and Tamaki Hiroshi promoting the SP on Mezamashi TV in HD (unsubbed)
(Uploaded by bmwracer @ D-Addicts)
Part 1 - Features them watching really entertaining footage of the behind the scenes filming (spoilery for just the first part of the SP!) MF:  
Part 2 - More behind the scenes for the SP at the beginning but is primarily showing the Nodame Orchestra playing their condensed version of Symphony No. 7 live, which is really great. MF:   
Mezamashi 2010.10.30 Langlang meets Nodame (unsubbed)
Ueno Juri meets Langlang, who performed the piano pieces they used for Nodame in the first and second movies and listens to him play a bit of Symphony #7 in A major. ♥
I hope you enjoyed some of extras! If you have anything that isn't listed here, please link us in the comments and I'll add it the post (with credit, of course!). ALSO, I know that the currently offline S-Projects soft-subbed the Bistro SMAP appearance and maybe more, so if anyone happens to have those subs, I'd be grateful for the hook up! Please leave a comment if you're downloading, this post took a bit of scouring. Cheers! ♥
Edit: Reupped 2013.02.04 :)