Alternatives to Dunlavy speakers?

I suggest Thiel.

Also, take a listen to the Vandersteen line.

In addition to the above, if you're not adverse to buying from a manufacturer without a US distributor, you could try Duntech, very similar designs, at least in their Classic series (many of their designs were originally John Dunlavy's while he was there). Also, Dynaudio designs, while not executed the same way even though their driver array would imply that they are (my understanding is they are a line source speaker, rather than a point source like the Dunlavys), can give you that "big" sound that Dunlavys do so well and are excellent speakers.

A product line that is conceptually very similar to what Dunlavy was doing is PBN audio's "Montana" series.

http://www.montanaloudspeakers.com/

The big Dynaudios mentioned by Rcprince are unique in their use of two tweeters, one above the other. This effectively preserves the wider-than-it-is-tall radiation pattern of the vertically spaced midranges and woofers. The result isn't really a line source, but it does produce a more uniform radiation pattern than the Dunlavy/Montana vertical symmetry around a single tweeter.

If you mean time and alligned speakers the bigies are Vandersteen, Thiel, and Meadowlark Audio.
-Vik