I've a question about multi-classing.
How do the following combinations sound?

Bard/Fighter
Bard/Demarch of Mask
Rogue/Demarch of Mask
Rogue/Bard
Fighter/Demarch of Mask
Ranger/Bard

Bear in mind that too much multiclassing will hurt your character's spellcasting abilities. Since a Bard is often used as a support caster and singer (and the best song is available at level 11 iirc you still have a few levels to spare even if you play a full party in normal mode).

A Bard has to be non-lawful and no race has bard as its favourite class still you may want to pick up a race without CHA penalty (half orc bards can be fun but they are not as good as humans or other races for instance).

-Bard/Fighter. 4 levels if you want weapon specialisation, the extra feats can be very handy to get lingering song (the feat every self respecting bard should have ASAP) and spell focus Enchantment, you could also take Armored Arcana in order to be able to cast spells while wearing armours and/or shields. Dwarves (the ones without CHA penalty) can be a good choice for the extra CON and the coolness factor.

-Bard/Demarch of Mask. This MC could work nicely but you'll need high CHA and high WIS meaning that points will be spread out (if you pick a female Drow that can still be doable) but a fulltime cleric would most certainly be more effective in the long run. The Bard's high CHA can be handy to turn undead (not that useful nevertheless in IWD2).

-Rogue/Demarch of Mask. Start as a Rogue (for skillpoints) and take a second Rogue level later on for Evasion and the rest as Cleric. Sneak Attack can be a very effective option, in that case put as many points as possible in STR and WIS, take only a few Cleric levels and the rest as Rogue (micromanagement eavy). Casting Command (1st level spell) with high WIS and spell focus enchantment will allow your character to use his/her sneak attack on the disabled foe. Of course if you're not soloing a fulltime Cleric could disable the opposition while a fulltime Rogue would get to use his sneak attack ability on the enemy.

-Rogue/Bard. Not a bad combo, 2 Rogue levels nicely complements a Bard's abilities. You could spare a few points for Alchemy and get the Envenom Weapon feat if you wanted to.

-Fighter/Demarch of Mask. Doesn't look so good I'm afraid. Taking fighter levels won't give access to more weapons or armours and will cripple the spellcasting abilities of this character. Especially if you take more than one fighter level. This can still be done especially if you are desperate to get extra feats (fighters get more feats than other classes) but I wouldn't recommend it.

-Ranger/Bard. Works nicely with just 1 Ranger level. You get two weapon fighting and ambidexterity for free when not wearing heavy armours (which a Bard as a spellcaster shouldn't wear anyway to avoid spellcasting failure). You'd have to take a Human or a Half elf character (ranger and bard are not the favourite classes of any race).

Multiclassing can be very tempting but you should keep your spellcasters as pure as possible if you can. In the long run taking more than 1 level in any other class will cripple the spellcasting of a character.

thanks very much for the feedback! It's been very helpful. Someone emailed me some really nice looking portraits and they really caught my eye.

I agree with caradhras but have a slightly different opinion on one char - Fighter/Demarch of Mask.
This can be very effective. Demarch are at best a mediocre cleric domain but clerics are really useful in 3E D&D.
The best is if you have just one fighter lvl since if gives you proficiency with all martial weapons which is very useful for this kind of build. Use any race that don't give xp-penalty. Maximize wis, str and con and put the rest in dex. Minimize int and cha.
You can take more fighter lvls if you play HOF and have reached cleric lvl 20 or so.

The same rules apply to all kind of fightertype-classes1/clericX MCs. Compared to a pure cleric you get your spells a little later but you get to use any weapon and get a class specific bonus (extra feat for fighters).