http://www.ebay.ca/itm/Genuine-Leath...item53fc516ce7

Where I got mine a while back...guys good.

Addendum:
Did some digging...since i realize that one of my n810's has a sweeet leather wallet
(might want to type that phrasing in instead of "book case"...you'll get a few more searches appearing)
...that is made by Boxwave......real beauty...real tight pro stitching
...and in most other models the inside of the leather cover
..whether it is "flip" or "book" model...tends to be blank...
or at best have 1 or 2 slots for sd cards....
but the n810 boxwave leather wallet has 3 slots for credit/id cards
and a slot at the inside "hinge" that is the size of the whole front cover...for whatever...
Sooooo. naturally I figured there must be similar for the n900....
Did some hunting and...found this by Boxwave....

http://www.boxwave.com/nokia-n900-ca...bwpdd/pf-tckk/

the proper aluminum flak jacket ....not a knockoff.
Decent price... on sale currently 1/2 price...
cheaper than pdair's version...and pretty slick.

AND...even better....

http://www.trade2w.com/Genuine-Delux...okia-N900.html

Just like my N810 Boxwave wallet!
Better! The sd card slots face inward ...
meaning less chance of them getting lost(never has happened to me with my boxwave... but you never know)
Stitching looks good ...and SUPER cheap....
$12...free shipping and a screen protector thrown in...
worth the risk....I'm gonna need a slick Corporate-Business-Man-Mogul-like-case for mah neo900 when it shows... ...put on mah white patent leather shoes ...turn on the bee gees on my neo900 and do mah travolta strut down mainstreet
...so I've just bought this case ...tell you whether it is worth it when it arrives.

Thanks for Asking the question man!
Else I'd never have hunted and would have gotten the easily searched for Aluminum Tank