Here are some places and ways to find some gems of old Missouri:
I have much better luck on Amazon than ebay, alibris, or alibris, etc. Though I have found incredible deals at these places as well, so they should not be forgotten. Pr. Andrew Gray of Iowa East says I am in the stone age and that bookfinder is the way to go. Whatever...
2. CPH has print on demand works available and a Professional/Academic catalog of books.
3. NPH has some older titles mixed around in its selections.
4. The CLC's Book House has some older treasures as well especially in their Theology section.
5. Anchor Books and Tracts, which is connected to the LCR, also has LOTS of old gems for very reasonable prices.
6. Concordia Lutheran Conference's Publishing House has a List of available titles which has tons of great stuff.
7. The OLCC has two old Missouri classics online: P.E. Kretzmann's Popular Commentary; and much of W.A. Maier's For Better Not For Worse
8. Pr. Rolf Preus has a multitude of essays here by his father Pr. Robert Preus (as well as himself and one by Pr. H.A. Preus). Not all of the essays fit within our historical parameters, but it is too excellent of a collection to pass by.
9. Repristination Press mostly has works from the period of Lutheran Orthodoxy, however, there are a few 19th Century American Lutheran works available and two William Dallman books, one on Gustavus Adolphus and one on Robert Barnes, which would definitely be considered L-TOM's.
10. Lutheran Legacy is another source of great stuff. In regards to American Lutheranism, they carry The Works of David Henkel (intro by Prof. Larry Rast) and The Justification of the Sinner Before God by Edward Preuss (intro by Prof. Roland Ziegler), an L-TOM if there ever were. There online store is here.
11. Christian News has tons of old classics for sale in its bookstore.
12. 1580 Press, run by Pr. Nathan Higgins, also has some works by early Missourians.
I am sure there are plenty of other places as well...so tell us about them!