Hi Walt,
The short answer to your question: All the material is available and some of the albums may be available.
In recent years, as you might know, Burt Bacharach Plays His Hits, Reach Out, and Make It Easy on Yourself have been reissued on CD. We've also had reissues of Casino Royale, Lost Horizon, After the Fox, What's New Pussycat, and Promises Promises, although I'm not sure which ones are currently in print. Burt's 70s albums have been reissued at various times in Europe and Japan, but they're not easily located. Do a search on
Amazon and do a search on eBay for the titles you're looking for.
(You could most likely locate the original albums on eBay if that's what you're looking for.)
If you want to catch up in one fell swoop, visit hiposelect.com. The label, a collector's quality reissue division of Universal, recently put out
Something Big, a five-disc box set that includes all of Burt's solo albums from Plays His Hits through Futures, including the rare live album and a few rare tracks. It's a pricey alternative, but it's a very well done set for Bacharach obsessives. Like me.