Add support to specify references in text.(May be like comment with references inside, or any other style)
There are many very similar suggestions about references.
Just combine them all into one and implement.
My opinion: The simplest way with in comment description style is the best.

Details:
Just add support for parsing comments like
/* ===Automation===
AddReference: mycode.dll
AddReference: somedll.dll
*/

This looks like comment and could be freely copy-pasted. But also this is reminder to add such references for code testing. LinqPad could automate adding references by parsing this simple text.