Well, my C240 is a 6 speed, but I know that doesn't count!
My BMW 535i is an automatic, but not for long! I am pulling out the automatic and converting it to a 5 speed manual next weekend.
I'd imagine that the operation would be pretty similar for a 300E. Since 300E sticks are so hard to find, one might be able to buy a readily available automatic and convert it!The only question mark would be availability of parts, in the US you might have to have the stuff shipped from Europe.
I had a pretty easy time finding all of the parts for my BMW swap, using a combination of used and new parts, the total parts cost was a little under $1000.