there is only 1 line of amps that randall now make which are pure solid state, the RX series. ive never heard these amps used on their own, but ive heard the RX120D half stack run with a dime distortion pedal and it sounds really good. Randall also make the G3 line of amps but they are hybrids, not sure how they sound but ive heard good things about them. If you want to go second hand I recommend ebay, there a dozens of solid state randalls on their all the time. I recently purchased my Warhead from ebay, best amp ive ever heard. check out these links:
http://cgi.ebay.com/Randall-Warhead-150-watt-Amp-Pantera-with-footswitch_W0QQitemZ130068817419QQihZ003QQcategoryZ10171QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
http://cgi.ebay.com/Randall-Warhead-Dimebag-Daryl-Signature-guitar-amp-head_W0QQitemZ200066767112QQihZ010QQcategoryZ10171QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
a classic head:
http://cgi.ebay.com/Randall-Century-170-II-2-Ch-Guitar-Amp-Head-150-watts_W0QQitemZ320068391217QQihZ011QQcategoryZ10171QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
hope that helps!