user81064: I've designed a circuit controlled by an Arduino Mega 2560 involving a number of external components all running on and sending out 5V signals. I'm now realizing that the 8Kb of SRAM on the Mega 2560 is insufficient, so I wanted to upgrade to an Arduino Due.  The Due, however, can't accept the 5V outputs from the rest of the components.
Is there an Arduino compatible 5V board with memory comparable to the 96Kb on the Due?
I know that level shifting is an option, but considering that almost every digital input on the board is being used, I'd rather not have to add so many level shifters to the circuit.  A voltage-compatible board is preferred.
I'm also not fixed on Arduino-compatibility.  If there is another convenient microcontroller development board available, I'd gladly consider it.
EDIT:
The Arduino is being used to read from a set of sensors that produce image data at a constant rate.  The data is recorded on the Arduino, then sent to a computer by USB.  The Arduino needs to store the whole image before sending it to the computer because performing a Serial write call delays the processor causing it to miss a data sample.  The ATMega2560 doesn't have enough SRAM to store the whole image at once.

user81064: The Teensy 3.5 seems to be exactly what I was looking for.

It is an Arduino-IDE-compatible 5V tolerant microcontroller board with a whopping 256Kb of SRAM and 64 digital inputs.  It pretty much blows away the Due in every way.

81064: <p>I've designed a circuit controlled by an Arduino Mega 2560 involving a number of external components all running on and sending out 5V signals. I'm now realizing that the 8Kb of SRAM on the Mega 2560 is insufficient, so I wanted to upgrade to an Arduino Due.  The Due, however, can't accept the 5V outputs from the rest of the components.</p>
<p>Is there an Arduino compatible 5V board with memory comparable to the 96Kb on the Due?</p>
<p>I know that level shifting is an option, but considering that almost every digital input on the board is being used, I'd rather not have to add so many level shifters to the circuit.  A voltage-compatible board is preferred.</p>
<p>I'm also not fixed on Arduino-compatibility.  If there is another convenient microcontroller development board available, I'd gladly consider it.</p>
<p><strong>EDIT:</strong><br>
The Arduino is being used to read from a set of sensors that produce image data at a constant rate.  The data is recorded on the Arduino, then sent to a computer by USB.  The Arduino needs to store the whole image before sending it to the computer because performing a Serial write call delays the processor causing it to miss a data sample.  The ATMega2560 doesn't have enough SRAM to store the whole image at once.</p>
 81064: <p>The Teensy 3.5 seems to be exactly what I was looking for.</p>
<p><a href="https://i.stack.imgur.com/NwXoam.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/NwXoam.png" alt="Teensy 3.5" /></a></p>
<p>It is an Arduino-IDE-compatible 5V tolerant microcontroller board with a whopping 256Kb of SRAM and 64 digital inputs.  It pretty much blows away the Due in every way.</p>
