this is all quite a lark, and not too taxing, but.

given a puzzle replete with this type of clue, and given a blank grid to start with, here is an example clue:

Across
1 R (nine letters)

<thought balloon>
hmmm.. well it could be "bitter end".. or it could be "first rate".. I'll just try one of those and see if it fits with 1 Down..

-joe (clueless on) friday

edit: more of a challenge for the cruciverbalist would be coming up with workable short phrases.