I saw one IRL today at Brompton Road.
I only saw the oak one, but it is a cutie. I felt it was similar in size to Brooke, very dinky, but still has some capacity for bits and pieces. The sizing on .com makes it seem like it is only a bit smaller than the regular Alexa but that is not the case, even the postmans lock is in minature. The shoulder strap is really long also so the bag sits on the top of your thigh.
I would have bought one, but the one they had in stock wasn't particulary nice leather, I already have an oak Brooke, and the sales are still to come! So maybe if I don't pick something up in the sales I might pick a mini Alexa up instead.
Also saw the Gracie aswell. I really liked the idea of it but seeing it IRL it is far too boxy, not particulary attractive IMO. The black one worked better than the oak one I think.