Last year BennVenn started making mods for Atari Lynx and his LCD Replacement Kit quickly gained popularity due to its cost (much cheaper than the McWill kit). This year BV is introducing the ElCheapoSD Cart for Atari Lynx, which lets you play Lynx ROMs from an SD card.
Atari Gamer has been working together with BV to help get the firmware developed. There's a rudimentary menu loader in place now, but we'll be making a more feature rich loader once the prototype hardware is finalised. You can see the cart in operation below...
This cart is much faster than the original Lynx SD, with 512Kib ROMs loading in under 2 seconds. It also has an onboard EEPROM, which means that games that have a save feature (mostly the recent homebrews) will work on this cart.
The best part is of course the price - at $45USD for the pre-order this is a steal! You can pre-order it here.