In the USA, you can get a SL1 from a number of places for under $1400 shipped, brand new, with a case.
The clean sound of Jacksons are usually great to spectatular, but I think this depends a little more on the clean channel of the amp you are using more than anything.
Les Pauls are okay, unlike Jackson, I would have to play one first, cause they commonly have quality issues.
Jacksons are far more consistent from guitar to guitar since they started selling them.
I would also suggest, USA BC Rich stuff, which is awesome, and just as consistent as USA Jackson stuff. Carvin makes some nice stuff. Their custom guitars cost less than USA BC Rich or Jackson STANDARD stuff.
How much were you looking to spend?