I'd go for the 2x10. You already have a 1x12 in the amp so this would give you the best of both worlds and open up options for recording. You could mic a 12inch and a 10inch and then chose the best one at mixdown, or blend them.
And the 2x10 configuration does not have less bass, it's just that the low end is raised slightly , say (total guess) 15hz higher. I find that this adds more high bass/low mid punch. Also, smaller coils have a quicker response and hence quicker attack.
I used to have the Laney mini stack like this, the extension cabs are the same size anyway so you won't be able to tell whether there's 2x10 or 1x12 inside.
If I was going for just the combo I'd say 1x12 although the Vibroverb 2x10's are sweet amps