Sonar Live backing tracks

Greetings all!  I have researched this thing to death but I thought I'd give everyone here a shot with an answer.  I am in a country/rock band.  We lost our bass player and can't find anyone to play.  We started experimenting with using Sonar as a backing track tool.  I have an OLD system with 256 meg of RAM running Sonar 2.2.  We are using a MOTU 828 interface.  This works great out of an open Sonar project.  I have not tried the playlist tool since we have only tried one tune at a time.
 
Now I'm looking for a new system.  I would like to have a laptop to take to live gigs.  I would also like to use Sonar or Live or something to output up to 8 possible backing tracks which would include bass, background vocals, chorus vocals, keys, some sort of percussion loop/click, and whatever else we come up with.  We typically play 4 sets that last about an hour or more.  Roughly 50 songs at most.
 
Here are my questions:
1.  Can Sonar 8.5 do this?
2.  If so should I use the playlist feature or load each hour long set into its own project?
3.  What type of hard drive and processor should I be looking at for the best performance and reliability? (I know the more RAM I have the better)
 
Those are my main questions at this point.  We would be using the system for backing tracks only.  Our sound guy would like each track on individual channels to aid in live mixing, so probably won't be using plug ins.  I have looked at Logic's Mainstage and like that idea quite a bit, but the Apple stuff is pretty darned expensive.
 
I've really enjoyed this forum so far.  Thanks for your help!