Have you told your LBS what your plans are for future bike purchases? Given the amount of money you're likely to spend in the future, I'd think a shop owner would go out of their way to help you find a cross bike that works for you, in the hopes of getting your repeat business on the other stuff you mentioned. At least, that's what my favorite LBS would do.

RE: commuting on aluminum - my first road bike was aluminum and I used it as a commuter. I then upgraded to carbon, and sold the aluminum. But, when I bought my cross bike, I got a Redline Conquest Pro in aluminum and it makes for a great commuter!

Good luck finding a cross bike that fits! Careful, cross is addicting!