http://www.esohead.com/skills?line=29

Looking at this, will some of the abilities be usable with a one-handed weapons without use of a shield? I wanted to make a Spellsword character, and only use a one-handed mace, and then magic - is it viable to do so from any of your experiences in the beta? My limited time in the beta only let me skill up two-handed weapons for the most part, so I never got a chance to see if this would work.

you can use magic even with 1h + shield

...

There is no single-handed skill line; it's either two-handed, one-hand + shield or dual wield.

I guess you could just go with one mace but I don't think (emphasis on think) that you will unlock any weapon skills that way.

EDIT: You could of course just let your caster be a pure caster and not use any of the (stamina-based) weapon skills, and just have the mace out because it looks cool.

I didn't try unlocking any skills, but fighting with a single weapon leveled up my weapon+shield skill line, so it might be possible...

Pretty cool to shield charge without a shield

There would be no benefit to only using half of the 1H and shield combo, if it's because of aesthetics my honest advice would be to choose if you prefer a bigger 2H weapon, or if you like dual wields (smaller weapons except two of them), or if you can handle having a shield cluttering up your character and go with the 1H and shield line as you seem to intend.

TL;DR: it would be less viable than if you use the gear the skill line intends you to use.