TBTH - I haven't found a way to get more than the 3 hotbars going (besides the shift+1, shift+alt+1, shift+ctrl+1, etc., to swap hotbars around - which incidently can be a real pain in mid-combat hence why I disable it!)

Training dummies = Kunzar Jungle - Tabernacle of Pain - training 'walls' which are free but you will need to do the faction quests so you are not KOS

Also - if you have a guild hall:
Training Dummy Supply Chest
Allow members to spawn training dummies for combat practice.
Purchase: 5p 500,000 status
Upkeep: 10g 2,500 status