I just found this product on DealExtreme, $2.33 each for 1 or 2, $1.81 each for 3 or 4 (though IIRC bulk prices require a little money for they are shipped in tracked package)

blue :
http://www.dealextreme.com/details.dx/sku.33310
orange :
http://www.dealextreme.com/details.dx/sku.33311

It may be a bit narrow, but buying 2 to rest the N900/N8x0 on won't break the bank.
I think that's the cheap stand I was waiting for, all my attempts at DIY credit card stands failed.