Removeable Internal SD card

Hi Guys (my first post!)

I'm keen to use a linux or android on a kobo touch -- love the device but I want a better reader.

I live in Toronto Canada and I have two locally purchased copies of model Kobo Touch N905-KOB-B.

I've opened them both, but I can find no removable microSD card. The location when the microSD is on videos/pix I have seen is filled by a soldered Samsung chip.

So some questions:

- I assume I need to find a model that has a removable SD card so that I can insert an image via a new card, or is it possible to use the external slot to boot to a new image? If so how?!

- If I purchase a new Kobo Touch, I guess this will be a 905C or possibly I could go for a Glo, is it highly likely I will get one with a removable SD card? Or are there models with fixed chips? I'd hate to pay out for another device model and just get another fixed chip device.

Thx for any help!
Neil