[TenTec] Argo 516 Memory Keyer?

[Curt]

I recently purchased a new Argonaut 516, impressed with the radio but sure 
miss a memory keyer.  My K1 has two message memories, even my lowly 
Rockmites have two.  The after-market RMK and Pico keyer chips for the 
rockmites cost about $5.

Has Ten Tec or anyone else produced a modification for the 516 to 
incorporate message memories into the keyer?  Seems it ought to be fairly 
simple and inexpensive to provide what I find to be a very useful feature.

Curt, KB5JO