Research 2000 for Daily Kos (8/31-9/2):
Dan Mongiardo (D): 41
Trey Grayson (R): 45
Jack Conway (D): 40
Trey Grayson (R): 46
Dan Mongiardo (D): 42
Rand Paul (R): 37
Jack Conway (D): 41
Rand Paul (R): 37
(MoE: ±4%)
Primaries:
Dan Mongiardo (D): 37
Jack Conway (D): 30
Other: 15
Trey Grayson (R): 40
Rand Paul (R): 25
Other: 18
(MoE: ±5%)
These numbers (both the primary and the general) line up very closely with the results that SurveyUSA produced back in August. Mongiardo and Grayson are still on top of their respective primaries, but Rand Paul's early strength continues to surprise. The DSCC would badly like to see Paul somehow pull off a miracle in the GOP primary, but it's pretty difficult to imagine his libertarian message grabbing hold of the Republican base. Certainly, it's even harder to imagine Paul winning the endorsement of many lower-ticket GOP officeholders throughout the state.
As it is right now, though, it looks like John Cornyn has a lot to be pleased with now that he's replaced a dead-in-the-water incumbent with the GOP's best player on their Kentucky bench.
http://www.swingstateproject.com/diary/5541/kysen-grayson-leads-all-comers