New GB Flash Cart in the works!

I'm building a more 'modern' flash cart for the GB. The question is, would you prefer it USB like a Drag'n'Derp? or SD card based like an Everdrive?

SRAM will be 128k to satisfy the LSDJ folk, what is the maximum ROM size you would like it to support?

4Mbytes is the most cost effictive, this would cover 99% of GB/GBC games.

The cart price is targeted at $50 but hopefully strong support will bring the price down.

Let me know your thoughts!