Thanks for the info, people. I didn't know about the Miyata/Univega tie-in. Inexpensive longer seatposts are readily available in the QBP catalog for virtually every diameter from 26.0 up, in .2 increments anyway.

It's interesting to me to hear all of the "too small" comments. I often think that the bikes I see pictured here in C&V are too large for their riders, based on very low seat heights...if your seat is 3" above the top tube, either you're unable to stand over the bike or your seat is too low and your knee angle at the bottom of the pedal stroke is much greater than it should be. This is of course tied in with the bar height and saddle/bar drop issue. The critical measurement for most riders should be the top tube length, and then picking the requisite stem for the correct reach. With a quill stem, the drop is fairly adjustable.

I am 5'9", and here's a look at my race bike's setup. It's effectively a 54cm frame also. I rode 9,500 miles last year on this and similar setups. I'm very comfortable on it.