I use 2 Macs and 3 PCs. I use RealVNC on the PC to watch the Macs using ARD (Apple Remote Desktop). Then I use HotKeyNet to broadcast to the VNC and the other PC's. It works about 95-98%.

For combinations, I would just theorycraft in your head for a little and see what comes out. Pick what you really want to play with. Pick what your final goals are. Pick what your playstyle is. Think about what would happen and see what happens out of it.
1) You really like rogues, so you pick a warrior and healer to go with you. You dump aggro off rogues onto tank and tank gets healed. Not bad, but melee have a hard time with facing and melee distance. What do you plan to do if a mob keeps distance (runs away to try to cast on you)? What do you do if you can't get behind the mob while tank is in front (mob keeps moving)? What if your healer gets aggro, how do you get it off again?
2) You pick 4 mages and a healer. What do you do against mobs that are fast melees (slowing casting)? What do you do against mobs that can't be slowed or CC'd? Do you want to work with all the macros to figure out how to CC 3 mobs?
3) You pick a mixed group (shammy, lock, druid, rogue, priest). Can you time their spells to work together (lock has instant DOTS, but shammy takes 2 secs to cast lightning and rogue has to wait for energy to rebuild)? Can you use most of the different classes abilities (only rogue would kidney, only shammy would earthshock, only lock would soul drain, etc)?
Etc, all of them have advantages, and disadvantages. After you thought it out, try to get a group to 10-20. After you get that far, you will probably be able to see if you would like it. It doesn't take that long and think of the time as learning what works and what doesn't.

Groups I have thought of:
5 druid: (stealth, healing, DPS, ressing, but melee range and facing issues)
5 locks: (DOTS from hell, have healing, no resses, fears for BG's, pets for CC and tanking)
5 hunters: (I have lvl 40's, ownage in every situation, costs lots of mana if you spam every shot, no resses, no healing, pets to DPS and tank)
5 shammies: (heals,resses, DPS, melee and casting, anti-casting, totems from hell)
5 pallies: (heals, resses, NODPS, melee, no casting, no anti-casting, mobs take 1-2 days to die, but you never die)
mixed but like groups:
3-4 casters and healer: (heals, resses, ranged, can't take melee in their face)
3-4 toughies and healer: (heals, resses, some ranged, can take melee in their face, but not all of them)
3-4 caster/healer and tank: (heals, resses, ranged, can take some melee in their face)

You can try