I don't have any grain on hand. Just planning using the LHBS that I just started going to. They don't carry Amber Malt and the listed malts are the closest from what I can tell.
melanoidin is often listed as substitute for amber, biscuit and aromatic. its a matter of preference here and what you want out of it. melanoidin is basically more intense munich.
Honestly I am just looking for an interesting note and layer of complexity. Sounds like Hoosier might be onto something with a mix of them. Slightly toasty, biscuity, and malty are all things I would be okay with. FWIW, I have something like 2.75# of Munich 10L and 9 oz of caramunich in there which is providing some maltiness...
Mixing the biscuit with either the aromatic or melanoidin might be the way to go...