The official website of Gateway 3DS have released a news.
04/06/2013

- Is it one microSD per game?

Currently yes.

- Must the microSD card size match the game size?

No, so long as the microSD card is larger than the rom size.

- Can it play games from other regions?

Currently no, however due to popular demand, we have launched an investigation into this possibility.

- Can it play Homebrew?

No.

- Are saved games working? Once you take out the game is the save file kept or lost?

We are currently working to fully support back up and restore of save data.

- Can Nintendo block Gateway with an update?

Anything is possible we would rather not speculate (As always, any system updates should be avoided)

- How big are the games and what is the minimum size for the microSD card?
Some range from 256MB to 4GB

- Can you play multiplayer local and mostly online?

Yes, but we advise not to use online features

- Do the game keep internet capacity?

Yes, but we advise not to use online features

- Is it upgradable?

Yes some aspects of the design will be upgradable.

- Can it run normal DS roms?

No, there are many alternative options for this.

- Suggested Retail price?

About $80/€65

- Availability: End of June. BUT until production has started, we are not accepting any pre-payment, therefore end-users should NOT pay until we indicate on our site that pre orders are officially open and payments from resellers are being accepted. PLEASE DO NOT PRE-PAY UNTILL WE SAY SO !