Since I purchased Lexa, I've received a number of inquiries from fellow shorties regarding the XS (43 cm) model.
For the record, I am an exactly 4'10.5" tall Green Girl with an approximately 27" inseam. The biggest obstacle for me was to find a bike with a low enough standover for me to actually stand over it.
The 2012 Lexa didn't come in the 43 cm size but according to Trek, the 2013 will include a 43 cm.
Her rear tires protrude slightly onto the backseats so I just tuck a tarp over her. No one would ever guess there was a road bike in my car.
As one might imagine, the smaller, women-specific geometry is somewhat restrictive in terms of accessory options.
I purchased a small U-lock but I've never used it since I discovered Lexa is small enough to roll into public restroom stalls when I'm out on long solo rides.
The smaller frame will only accommodate a single bottle cage so I always wear a Nathan Intensity hydration vest. I put sports drink in the bottle and water in the hydration pack.
In terms of tire replacement, I am currently using 650c x 23mm Continental Ultra Gatorskin Tires.
For spare tubes, I purchase standard thickness butyl tubes in size 650c x18/23mm with 48mm long presta valves.
When I travel with Lexa, I carry two spare tires and a few extra tubes because I know the 650c size is not common like the 700c.
The only modification I had to make to the Serfas Speed Bag was to trim the velcro straps since they were extending past the saddle and irritating me when I was cycling.
Lexa was absolutely one of the best investments the Green Girl ever made.