Sorry, was away in Singapore for a couple days so didn't reply. Managed to pick up K-On! Puchi TBSishop version and K-On! Nendo Live Stage Mio/Ritsu sets while down there!! The Mio/Ritsu Live stage set was only SGD120, which is just about RM300 given the weak exchange rate now!

The W400UV is 394 x 182 x 166mm, and you can see it here:-



And here's a pic of it with Nendo Puchis. My FSN Puchi sets are stuck in various cases which I was lazy to open (the XL-Shop ones. They don't open in front and require you to lift the entire case, annoying if you have things standing on top) but FSN + Extension should be 16 Puchis + 1 Nendo (Berserker) and so I used 16 Puchis and 1 regular Nendo to show what it looks like.



Berserker might need slightly more space than Nendo Saber because of his big arms, but there's more than enough space in here for that. I've also tried stuffing them into the large Tokutokuya Round Display Case, and they do fit.



This case might be better if you want to save space and it's 345 x 134 x 133mm. They look quite bad in this pic because the base is flat, and so you can't really see the ones behind, but iirc Tokutokuya does have a version with a 2-level base which is raised at the back. No versions with 3 levels, though, but given the size of the case I doubt a triple-level base could hold Nendo Puchis stably. The single-level Round Display Case is much better used for the display of regular Nendos, though, like this:-



If you used regular Nendos with less accessories (like without Ritsu's drums and Tsumugi's keyboard) you could probably fit 7 Nendos in one case, although I'd guess that anything more than 6 would look cramped. There's also a medium Round Display Case which is 214 x 134 x 133mm, and it fits 3 Nendos really nicely. Could probably fit 4, maybe 5 normal Nendos which don't have accessories (Mashiro's table takes up a ton of space).



I'd try and get the W400UX (The LW is the same, just with 2 levels, but 3 levels would be much better for Puchi. For regular Nendos you can try the 2-level model) from BTS if possible (they should still have some stock, although some might be cracked - maybe ask for a discount if all they have are the cracked ones). If they're sold out, then the Tokutokuya large Round Display Case is a good option. I don't have a 2-level base to show you, though, sorry!