nkhs

About 320mm long (3x100mm fans +guestimate of spacing)

I would avoid the 25" monitors if possible, they are really small vertically. I actually just bought (arrived this afternoon even) a LG 29UM55-P for $250 used ($400 retail) off of Amazon and if you're in the US I believe they still have some left in stock.

not really i play on a 25" 21:9 and it like 1 inch less then a my 24" 1080p and i would much rather play on it then the 24" it just something you get use to if you normal play on a 27" then a 25 will look tiny... but if you come from a 21 or 23 inch its look nice and the pixel density is better then on 29"

Thanks for everything dude!

I also recommend you get this app if you decide to get into 21:9 gaming because whenever there is an issue with a game not supporting the aspect ratio you load this little baby up...http://www.flawlesswidescreen.org/And bam you are good to go on basically every game that has issues.

Non sfx won't fit

umm, check on the 800W PSU's and check their dimensions and such, getting a better PSU can be helpful in the long run.