Try corn syrup. Here's a link to a recipe without egg white. Note the lede at the beginning of the recipe (pay no attention to the link name, it is a marzipan recipe) :http://smittenkitchen.com/2006/12/almond-joy/

I wonder what value the egg white adds. I make a marshmallow with egg white, but it goes into a hot mixture so it cooks enough. Here I do see now the "slow" food processor wouldn't do the trick.

Fresh egg white are not shelf stable, these will definitely cause spoilage or at least the potential for salmonella contamination. Marzipan itself is considered shelf stable, but it can dry out and crack.

Thanks for the thoughts - I will test it out and report back on the results, while trying not to eat it! hardlikearmour your comment makes me think this is why many marzipans are overly sugary.

I agree with HLA. Just leave it as is. Adding moisture adds potential for spoilage.

I think it would be relatively shelf-stable as a refrigerated product. The sugar should make the mixture hygroscopic enough to dessicate bacteria. My thought is it would eventually grow mold.