HAHAHAHAHA I DID TOO!!!!!
Ahhhh this makes me so happy. My brother and I, like many, were so obsessed with all the LucasArts adventures, so naturally I mailed them in my idea. I also got a letter back. IIRC it wasn't from a lawyer, but it was definitely a soft "no." There's a chance I still have that letter somewhere.
Man, I am not a "good old days" kind of person but the 80s (well, late 80s early 90s) really were a different time.
Amazing. Just texted my mom asking if she has the letter. I doubt it all these years later but I'll share it if she still has it!
Edit: no dice!