Welcome to TE!
Surlys (Surlies?) tend to have unusually long top tubes. (I could ride a Pacer in a size smaller than I "should" be based on my inseam, but a Cross-check is out.)
It's awesome that you found a shop that will let you rent nice bikes. If it makes your heart sing, get the Madone.![]()
If, however, you really want some other points of comparison, consider: Specialized Ruby (carbon; more expensive for same componentry, unfortunately). Jamis Quest Femme (steel; perhaps upgrade components?), Cannondale Synapse (carbon), or even the SuperSix if you feel so inclined. (I've been looking at all these bikes (except the Synapse), as well as the Madone, as my next bike, for similar purposes as you.) You might try Giant's Avail Advance (carbon) line, but I've found them to be not-so-friendly to my short torso. Your mileage may vary, of course.
(Is 17mph a sedate pace? Geez. I must be doing "sedate" wrong!)