US Patent 5675038 (http://patft.uspto.gov/netacgi/nph-Parser?Sect2=PTO1&Sect2=HITOFF&p=1&u=%2Fnetahtml%2Fsearch-bool.html&r=1&f=G&l=50&d=PALL&RefSrch=yes&Query=PN%2F5675038)
(http://patft.uspto.gov/netacgi/nph-Parser?Sect2=PTO1&Sect2=HITOFF&p=1&u=%2Fnetahtml%2Fsearch-bool.html&r=1&f=G&l=50&d=PALL&RefSrch=yes&Query=PN%2F5675038)I would bet that a cold (~ 0 C) saturated solution of ammonia in ethanol would form a blue solution w/ addition of Na, or Li.
I would bet it has to be a lot colder. I tried this a few months ago at slightly under 0 C and could not get lithium to dissolve in ethanol/ammonia solution. I can't say if Na will work because I'm not allowed to play with explosives. :(
I'm guessing you have to approach conventional birch temperatures, and if you're going to go through the trouble of setting up to sustain subzero temperature, you might as well just use ammonia.